Biden must weigh who can help him win, who is simpatico with him, who has the broadest appeal and who could be called on to take over.

Joe Biden’s choice for a running mate could be the biggest political decision of his life — and the most significant vice presidential selection since Abe Lincoln crossed party lines to tap Andrew Johnson in 1864.

The former vice president's dominance in Tuesday's Florida, Illinois and Arizona primaries  gave him a clear path to the nomination and license to get serious about a ticketmate. His VP pick will not only affect his chances in November; if he wins, it will be of overwhelming importance to the nation going forward.

Biden narrowed the choice during Sunday’s debate with Sen. Bernie Sanders with the surprising declaration that he will name a woman. That was long suspected. What caught many off guard — including Sanders, it seemed — was that Biden made the commitment so early in the process. 

Diversity, geography, ideology and age

The list of factors Biden must weigh is long. Does he pick a person of color? Someone who will please Sanders supporters? A person who is considerably younger? A candidate with geographic strength, particularly in the Midwest? 

The selection of a running mate is part of the political chess game, and versions of the questions above are always in play. But in the 2020 race, with 77-year-old Joe Biden on path to the nomination, the considerations are magnified. Since a President Biden might serve just a single term, voters will look closely at his running mate with the thought that she could be called upon to take over.

“Look, I view myself as a bridge, not as anything else,” Biden said recently at a rally in Detroit, alluding to younger Democrats who are “the future of this country.” Defining that future begins with the vice presidential pick. 

Biden has remarked numerous times that his running mate’s positions must be “simpatico” with his own. In an interview on MSNBC, he added, “It’s really important that the next president is able to do what Barack was able to do with me: turn and hand over 10, 20% of the portfolio and say, ‘you do it as if you were president,’ because there’s so much that lands on a president’s desk that he can’t, or she can’t, do it all by themselves.”

The challenge for Biden will be determining how many different qualities he can combine in a single partner, without suffering diminished returns. However, there were so many diverse candidates in the initial Democratic field that it will be impossible to appeal to all of their supporters. 

Who can help Biden defeat Trump? 

Minnesota Sen. Amy Klobuchar, a fellow moderate and a proud Midwesterner, would be a logical pick. Her 13 years in the Senate and significant legislative accomplishments suggest she could handle much of Biden’s portfolio. Michigan Gov. Gretchen Whitmer is probably on Biden’s short list, having proved herself on the national stage by skillfully delivering the Democrats’ response to Trump’s State of the Union message. 

Should it be a black woman? Rep. James Clyburn, who was instrumental in rescuing Biden’s candidacy by endorsing him just before the South Carolina primary, told Axios, “I prefer an African American woman.”  

California Sen. Kamala Harris would seem to be a solid choice. However, her home state is virtually guaranteed for any Democrat, and a November poll by the Public Policy Institute of California showed Harris with just 8% support among primary voters. Other names that come up frequently are Rep. Val Demings, the former chief of police in Orlando, whose national profile rose when she served as a manager on the House impeachment team. Also, Stacey Abrams, the former minority leader in the Georgia House, who lost narrowly to Gov. Brian Kemp in the 2018 gubernatorial race but has since drawn much national attention. 

Should it be a Sanders supporter? Massachusetts Sen. Elizabeth Warren shares many of Sanders’ positions, but she has yet to endorse either Sanders or Biden. Sanders supporters adore rising star Alexandria Ocasio-Cortez, the New York congresswoman who has campaigned vigorously for Bernie. However, at age 30, she’s five years short of the constitutional age requirement to serve as president or vice president.

Does geography count? Klobuchar could prove valuable in the Midwest, where Trump managed to flip Iowa, Wisconsin, Michigan and Ohio in 2016, giving him the victory over Hillary Clinton. Demings could help in Florida, which helped re-elect Obama in 2012 but then gave Trump its 29 electoral votes in 2016 based on a raw vote margin of just 1.2%.

Complicating matters is the very thing that made Biden the all but assured nominee: His chances of beating Trump. As the old white guy with decades of experience, he is viewed by many Democrats as the safest bet. So, would he tamper with that by picking an unsafe running mate? Does he risk backlash against a woman, an African American, a member of the LBGTQ community, or an ultra-progressive? 

It’s often said that picking a running mate is a president’s first real decision. For Joe Biden, it might also be the biggest. 

Peter Funt is a writer and host of "Candid Camera."