This is the first major decision a potential president must make, so it always raises interest as a test of the candidate's judgment. Also, since both of our candidates are already well beyond normal retirement age, there is no guarantee they will live through their term of office. Let's take a look at who may be under consideration:
No, Hillary is not going to tap Bernie Sanders to run with her. Yet, it would help unite the progressive left behind her candidacy, but Sanders is not one to shut up and smile. I don't think he would have much interest in standing there silently for four years when he could be screaming and shouting about issues it he Senate. Even if Clinton wanted him, Sanders is not one to do it out of party loyalty, since he really only joined the Democratic Party to run for President. He has been an independent for virtually all of his political career. Sanders also has way too much baggage. His support for increased taxes on everyone, for support of various Communist governments in the 1980's, and his outspoken support for a range of unpopular leftist issues would be too much of a feast for the Republican political advertisers. Clinton would never want that distraction.
Remember way back that the beginning of the race when Martin O'Malley, Lincoln Chafee, Jim Webb, and Lawrence Lessig were running? Neither does anyone else. None of them ever caught on with anyone and are not likely to get much consideration for the VP slot.
Clinton is less likely to pick a Washington insider since she has been an insider herself for the last quarter century. The Senate is the most common place for any candidate to pick a running mate. In a year when voters seem particularly anti-Washington, this would seem like a bad choice on a political level. If she does pick someone from Washington, it will likely be someone young who has only been in town for less than a decade.
Sherrod Brown, Senator from Ohio, has gotten a fair amount of press speculation for VP. Brown has a relatively solid moderate record for a Democrat. He tends to favor protectionism and has supported legislation to reign in Wall Street. That could help him with Sanders supporters, although it may play as a contrast with Clinton's record. No Republican has ever won the White House without Ohio, so anything Clinton can do to help her chances there probably makes sense.
Tim Kaine, Senator from Virginia, and a former Governor, is not much of an insider, but does come from what is now an important swing State. He would be a relatively bland and safe choice. His selection would not excite the progressive left, but would not scare off moderates or anti-Trump Republicans either.
Mark Warner, the other Senator from Virginia, and also a former Governor. At age 60, he does not have the youth of many others under consideration, but has won multiple elections in a relatively conservative swing state. He was seen as a possible Presidential candidate in 2008, although he declined. He may have done so out of deference to Clinton's run, which would work in his favor now, or because he has skeletons, which would still be an issue for VP. Assuming no skeletons, he is again a relatively safe moderate choice.
Cory Booker, Senator from New Jersey, probably has not been in Washington long enough to be considered a Washington insider. He tends to be traditionally liberal and from a solid Democrat State. However, many on the left see him as a Wall Street sell-out. His selection would not help Clinton with the Sanders supporters. His liberal policies probably would not help with moderates or anti-Trump Republicans.
Martin Heinrich, Senator from New Mexico, came to the House riding the Obama wave in 2008. He won his Senate seat in 2012. He holds a fairly traditional liberal Democrat position on most issues, but tries to reach out to Republicans where possible. He is young, reasonably bright and looks good in a suit. That's probably enough for consideration.
Evan Bayh, Senator from the very Republican State of Indiana, an impressive feat for any Democrat. He is from the conservative wing of the Democratic party. His father, Birch Bayh, was also a Senator. Bayh was seen as a Democrat who could help make inroads into Republican territory, but is considered an intellectual lightweight and without much going for him. He also has some controversies involving business deals. Clinton has enough of her own business deal controversies without adding more.
Bob Casey, Senator from Pennsylvania, would be an interesting choice. He is relatively moderate and from a Democratic leaning State that always seems to be in play. The fact that he is a pro-life Democrat might turn off some, but probably not a deciding factor for voters considering between Trump and Clinton. Abortion aside, Casey seems to follow the Party line on most issues. His father was once Governor of Pennsylvania, making him appear part of the long time political class that voters seem to dislike this year.
Elizabeth Warren, Senator from Massachusetts, is part of the Washington scene, but is still seen as a progressive outsider because of her Wall Street opposition. Her selection for the ticket would make Sanders supporters happy, but not much of anyone else. Warren holds very liberal positions on most issues, which may not play well out of Massachusetts. There is also little evidence that she would want to hold her tongue and stop criticizing Clinton's moves to the right. Having two women on the ticket may also be a little much for some voters.
While on the subject of female Senators, There are a number of others who may get some consideration: Claire McCaskill, Jean Shaheen, and Amy Klobuchar. A two woman ticket seems like an unlikely decision for Clinton, who would want to remain as centrist as possible after the nomination. Also, with the Senate trying to win back a majority, putting any of these States in play for a new Senator would be seen as a problem. I don't see any of them as a likely choice.
It would be highly unusual to pick a cabinet secretary with little electoral experience. These folks tend to be untested in the public limelight. They also tend to be more focused on policy than winning elections. Often, they are involved in policy decisions that can create political firestorms. They also tend to associate the campaign with the prior administration. Nevertheless, several, Obama secretaries seem to be under consideration this year.
Julian Castro, Secretary of Housing and Urban Development, was put forward as a possible choice last year. He is young, of Mexican descent, and has been seen as a rising star in the Party. Still, he has little electoral experience and is tied to the Obama Administration Castro was a favorite when Clinton thought she might be facing a Hispanic Cruz or Rubio opponent. But after Republicans picked a regular white guy as usual, the need for a Hispanic on the ticket seems less important.
Tom Vilsack, Secretary of Agriculture and former Governor of Iowa, briefly ran for President in 2008 before dropping out and endorsing Clinton. He tends to favor an aggressive foreign policy and did not seem to support the President's decision to leave Iraq. Secretary of Agriculture usually leaves one out of the controversial issues. He is seen as being too cozy with the agribusiness industries for many of on the left. The leap from Secretary of Agriculture to Vice President seems like a long one to me.
Tom Perez, Secretary of Labor, former Asst. Attorney General, has spent most of the Obama Administration on civil rights issues. I figured I would throw him in as long as we are looking at Obama cabinet members, but he seems unlikely as well. His involvement in investigations of controversial civil rights cases like Trayvon Martin, Sheriff Joe Arpaio, and voter ID cases may make him seem like too much of a Democratic partisan. He is Hispanic, which could be seen as a plus. But lack of any real elected office makes him look more like an Washington Bureaucrat, out of touch with real America.
Governors are often seen as chief executives only on a smaller scale. The tend to lack foreign policy experience, but are seen as leaders with political savvy. In the last 50 years, five of eight Presidents have been Governors (Nixon, Carter, Reagan, Clinton, and Bush 43). Two others, Ford and Bush 41, moved up from Vice President. Only one, Obama, had only legislative experience. Governors, however, rarely get chosen as VP. I can think of only one who ran on a ticket in the last 50 years: Spiro Agnew, and that did not go well.
John Hickenlooper, Governor of Colorado has been discussed. The state is probably leaning Democrat anyway and is not that large. Hickenlooper lacks any foreign policy experience. But since he is balancing out a ticket with a former Secretary of State, that should not be an issue. The head of the State that is known as the leader in pot legalization would bring that issue to the national scene. It is probably a winning issue for Democrats, so that may be a positive factor.
Andrew Cuomo Governor of New York is probably an unlikely pick. Cuomo comes from a political family (his father was Governor and also discussed as a Presidential Candidate). Polls show voters want to see some different names from the ones they have always seen. Cuomo is also from the same State as Clinton, usually seen as a problem. Electors cannot vote for a President and Vice President who are both from their home state. This means there could be an issue if the New York electors were needed to elect the whole ticket. This could create a problem that would prevent them from voting for the Vice President.
One other woman who could get some consideration is Gina Raimondo, who was elected Governor of Rhode Island in 2014. She has little record on national issues, being much more focused on State and local issues. At age 45, she is a generation younger than Clinton, who has had trouble with attracting the votes of younger women. Even though Raimondo would make it a two woman ticket, the diversity of age may be an attraction.
Out of the Box Picks
Xavier Becerra, a twenty year veteran of the US Congress, from California and House Democratic Caucus Chairman makes Becerra an insider. He has campaigned heavily for Clinton in the primaries. He does not have much of a national reputation. Being Hispanic could be a plus for Clinton. The fact that he is a practiced politician and known campaigner also work in his favor. He has taken relatively liberal positions, even for a Democrat, but is not seen as a radical.
Charlie Crist, former Republican Governor of Florida, turned Democrat. Crist is from a swing state, but has not been particularly popular there since he changed parties. He could start a conversation about how the Republicans have gone too far off the mainstream. That could have appeal for independents and anti-Trump Republicans. Democrats, however, may pause at having a former Republican that close to running the Democratic Party.
Deval Patrick was Asst. Attorney General during Bill Clinton's administration. He left to go into private practice before becoming the Governor of Massachusetts nearly a decade later. As with any Massachusetts Democrat, he has taken quite liberal positions on many issues. Being an African American may help to keep those voters voting with some enthusiasm, even if not the levels they showed for President Obama. Patrick also worked for Bain Capital, Mitt Romney's company. That would certainly raise questions among the anti-Wall Street crowd. Patrick as VP would not be a pivot to the center as Clinton is expected to make, and would not particularly grab the enthusiasm of Sanders supporters.
Joe Manchin, Senator and former Governor of West Virginia is nominally a Democrat but seems to support the Republicans on a great many issues, including guns and the environment. He refused to endorse President Obama's reelection in 2012 due to policy differences. Manchin comes from a conservative State that Clinton likely would still not win. Manchin would probably be to the right of Trump on many issues and is outspoken enough that he might start more political fires than he extinguishes. Manchin would also alienate the progressive left. So while some pundits have put his name on long lists of VP possibilities, he seems a real long shot.
Joe Biden, Vice President now and continuing? While we are on the subject of real long shots, Joe Biden could continue in the position of VP for another four or eight years. He is experienced and has not been overly criticized. There is no term limit on VP as there is for the President. Biden would tie Clinton more closely to the Obama Administration. I don't know if that is necessarily a bad thing for voters, but she probably wants to be seen as her own person. At 72, Biden is also older than all the other candidates and is probably ready for retirement.
Wesley Clark, retired General who has been an active Democrat since retirement, could be an interesting choice. It could help with voters who think Democrats are weak militarily, something that has long concerned Clinton. He comes with little political baggage. At 71, however, Clark is likely going to have his age be an issue, as is his complete lack of political experience.
It is hard to guess where Clinton is headed with her choice, given the lack of public discussion on the issue. I would say that Sherrod Brown may be the favorite in this crowded field, but probably would not give him better than five to one odds. Julian Castro also has received a fair amount of attention. Tim Kaine also makes my list of likely short-listers.