Candidates’ résumés and policy proposals alone do not tell us how they would govern. President Donald Trump, elected in part by those who thought a businessman could run a government like a business, has given new life to the term kakistocracy—the worst kind of government, run by the worst kind of people. Both Jimmy Carter and Bill Clinton stumbled in their first year as president because they thought their experience as governor of a small state prepared them for the White House. Neither established an effective personnel-management system at the outset, and both left sizable gaps in their teams at levels below the Cabinet that took years to remedy. Both mistakenly thought that dealing with Congress would be similar to dealing with the Georgia or Arkansas legislature; neither established a smooth process to run the White House early on.

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Whoever is elected president in 2020 will face similar challenges, but also will have to deal with a tribalized and weaponized political process, regardless of whether the new chief executive enjoys majorities in both houses of Congress or control of the government is divided, as it is now (and was for six of the eight years of Barack Obama’s presidency). A president will have to contend with an obstacle course to get executive positions filled, much less judicial nominations, and will also face a court system that itself is becoming more partisan and divided along stark ideological grounds. The next president will have to deal with a political system ever more skewed by the unrepresentative nature of the House, the Senate, and the Electoral College; the role of big and dark money; and the lack of voting access for large numbers of Americans, partly as a result of voter-suppression efforts.

This is the frame in which voters need to evaluate candidates for president. Whether Elizabeth Warren’s Medicare for All plan is workable and fiscally sustainable means little if, as president, she faces either a Republican Senate or one in which Democrats have a slender majority—a majority that would include moderates and conservatives such as Kyrsten Sinema and Joe Manchin. Ditto for Joe Biden, Pete Buttigieg, Amy Klobuchar, and other candidates who have less radical plans to reform the health-care system. Warren’s road map depends on a huge expansion of the Medicare program, made free to millions and done via budget reconciliation, which requires only 50 votes in the Senate. But the reconciliation package would have to include a huge tax package to pay for the immediate and long-term costs—something that would be a very hard sell to the Manchins and Sinemas, among others. One can be certain that, if Democrats win the White House, the Republicans in Congress will fall back on the game plan they used for 2010 and 2014 with Obama as president: Vote in unison against anything the president proposes or supports, and delegitimize and try to undermine any policies that still get through and are enacted.