Paul Simon’s “Bridge Over Troubled Water” was an obvious choice for a convention striving to be one – and much more apropos than his “America,” the adopted theme of the Bernie Sanders insurgency. Fans couldn’t help but notice, however, that Simon had chosen a number that was sung by his estranged former partner Art Garfunkel, of whom he recently told NPR, “Quite honestly, we don’t get along.” Simon’s rendition was in that way analogous to the Democratic National Convention: a paean to building a bridge sung over the unmistakable crackle of a burning one.

Much depends on the Democrats’ ability to cobble together this particular piece of infrastructure. The enterprise hasn’t been helped along, though, by the not entirely shocking (and possibly Russian-engineered) revelation that Democratic officials connived against the candidate who was not a Democrat for most of his career.

Many Sanders supporters are new to politics, and it shows in their frequently heard promises to vote for a minor-party candidate or sit the election out rather than choose between Hillary Clinton and Donald Trump. Sixteen years ago, a similar impulse for perceived purity led many liberals to reject another centrist Democrat, Al Gore, in favor of activist Ralph Nader, which may have helped give George W. Bush his hanging-chad-thin victory. The once-popular notion that there was no substantial difference between Bush and Gore looked especially absurd in the wake of the Iraq invasion.

There is no need to wait for such a monumental event to reveal as preposterous the current claims that the choice between Clinton and Trump doesn’t matter.

To begin with, Clinton would be one of the more politically seasoned presidents upon her inauguration, while Trump would be the least. Moreover, in his convention speech Monday, Sanders himself reminded the faithful of the stark differences of tone and ideology between Clinton and Trump on immigration, the environment, health care, and more, concluding, “The choice is not even close.” Sanders went further on Tuesday by cautioning his supporters against voting for Green Party candidate Jill Stein.

The Democratic Party has fired its chairwoman, changed its platform, and made other concessions to Sanders’ improbably successful but ultimately losing campaign. And after a long and sometimes bitter rivalry, Sanders, in contrast with Trump rival Ted Cruz, offered a remarkably full-throated endorsement of Clinton. So did Michelle Obama despite her husband’s hard-fought contest with Clinton eight years ago. The first lady reminded the convention of the power of breaking historic barriers by noting that she, a descendant of slaves, now lives in a White House built by them – and that Clinton’s election would be another such milestone.

Amid enduring dissent, some of the convention’s most successful moments so far have appealed to unity among people – including the kinds of people, like undocumented immigrants and the disabled, who have been targeted by Trump’s divisive rhetoric. But the greatest test of the party’s tolerance is taking place within.

—The Philadelphia Inquirer, July 27