There is a persistent myth in American politics that a superb running mate can push a presidential candidate over the top, either in terms of the popular vote or in the electoral college. But there is precious little evidence from history to indicate that this is so.

Vice presidents simply aren’t that consequential in our system of government, and the strengths and weaknesses of the presidential candidate himself (or herself) determine the outcome, along with external factors like the state of the economy, war versus peace, natural disasters, pandemics, etc.

What a running mate can do, however, is to become a drag on the ticket. Sarah Palin is the most famous example of a potential vice president whose missteps — and whose unfair vilification by the media — proved to be a distraction from the messaging of, in her case, John McCain. And that is the scenario that Joe Biden must avoid at all costs: a running mate who adds to the long list of headaches, liabilities and burdens which his campaign already shoulders.

Presumably, Biden and his key advisors feel that, because of the historically high disapproval ratings of President Trump, what they need to do to win in 2020 is avoid making horrendous mistakes. That may be slightly optimistic, but no one can say for sure that this low-risk strategy will not work. Step one, therefore, is to choose a running mate who doesn’t stink.

To that end, I would like to suggest that Biden consider the attractions of California Sen. Kamala Harris at a potential vice-presidential nominee.

First, Harris has the experience, intelligence and gravitas to be a credible president of the United States, if “Sleepy Joe” should someday soon opt for eternal rest. This is key, because a selection like Stacey Abrams, although exciting to some progressives, would leave Biden open to the charge that he is thrusting a neophyte onto the national stage and possibly even into the Oval Office. Voters would perceive the obvious risk. Harris, by contrast, as a former California attorney general and as a sitting senator, is ready to roll.

Second, Harris can plausibly claim to be both moderate and progressive. Her record is long enough that it includes areas of vulnerability, yes, but it is also multifaceted enough that Democrats and liberals will be able to see in it what they want to see, which will vary from voter to voter. Harris is also smart and wily enough to pivot from the center to the left, and back again, as circumstances demand.

Third, Harris has proven that she can admirably fulfill one of the most important roles that a running mate has: that of attack dog. Harris excels in this regard. She made her only real splash as a presidential candidate by viciously attacking the record of Biden himself on the issue of busing. Harris, however, had the good sense not to press those attacks, because she (rightly) foresaw that Biden could emerge as the nominee, and she did not want to jeopardize her political future.

As Biden’s running mate, Harris would not be similarly demure. She would be unleashed to savage Trump, Mike Pence and the whole GOP over and over, while Biden smiled politely (some would say vacantly) and played the role of unifier and Mr. Nice Guy.

Fourth, Harris is a woman of color, which means a lot in today’s Democratic Party. To mollify feminists, Biden already had to concede that his running mate will be a woman (for some strange reason, he didn’t specify a non-man, which would have been more “woke,” but I digress). The truth is that, if he chose a white woman like Elizabeth Warren, he would still be seen as an agent of white privilege by many leftist firebrands. A considerable portion of the Democratic Party is, to be blunt, done with white people in general. By picking Harris, Biden would demonstrate that, although in the short term the party’s standard bearer is a tired, old, white guy, in the medium term the Democrats are ready to turn the page in terms of race and gender.

It should go without saying that elevating Harris to the role of president-in-waiting will also provide the Democrats with the opportunity to brand any and all attacks that Republicans make against her as VILE RACISM. We know from past experience that, the more nervous Democrats become about the viability (including the mental capacity) of their candidates, the more likely they are to fall back on charges of racism and sexism in order to motivate their base.

Given the glaring vulnerabilities of Biden, we can expect that the 2020 campaign will be the most grievance-laden and “intersectional” of all time. Harris is ready to play her part.

So, Joe, as you can see, the merits of Harris as a potential running mate are legion. If you want to win in 2020, first do no harm, and choose a vice presidential candidate who will refrain from tanking your campaign — that, after all, is your job. If possible, choose a running mate who can add some dynamism and a little soaring (or searing) rhetoric to your yammerings, but don’t expect to win because of the woman standing next to you. That just never happens.

If, then, Biden wants to win, he should choose Harris. She gives Sleepy Joe a fighting chance.

(Nicholas L. Waddy is an associate professor of history at Alfred (N.Y.) State College.)