Now that the Twilight in America convention is over, Democrats have a prime opportunity to change the tone of this election for voters who may be despairing of the dark, apocalyptic picture painted by Donald Trump.

The trick will be in highlighting the many good things going on in the country while acknowledging — and owning — the problems. This nation has had a Democratic president for nearly eight years. That's too long to blame those who have gone before. The triumphs and losses must be shared by Democrats and, importantly, the Republicans who control the U.S. House and Senate.

That, however, paves the way for a centrist approach that holds the greatest promise for compromise and action. America desperately needs to put aside gridlock and strictly partisan approaches to problems that are too multifaceted for a one-sided solution.

The selection of U.S. Sen. Tim Kaine of Virginia is a strong and needed signal that Hillary Clinton is making that pivot. Minnesota can actually lay a little claim to Kaine, who was born in St. Paul before his family moved to Kansas City, where he was raised.

Kaine has been a mayor, governor, senator and chair of the Democratic National Committee. He is a classic centrist. Fluent in Spanish, thanks to a year of missionary work in Honduras, he has spent a career threading his way between right and left. As mayor of Richmond — a city whose Monument Avenue is lined with statues of leading Civil War figures — he issued a formal apology for slavery. As governor of Virginia, he had a reputation for bipartisanship. In the Senate, he gained expertise in foreign affairs. This is a choice built for governing, not just campaigning.

Kaine will make some Democrats uneasy. As a Catholic, he personally opposes abortion, although he says he supports the legal right to choose. He's pro-TPP and wants less regulation for banks. That will rankle supporters of Sen. Bernie Sanders, but they should look at a Democratic platform that is as far left as the GOP platform is far right. It bristles with progressive favorites, such as a $15 minimum wage, more affordable housing, closing the racial wealth gap and strong climate-change initiatives.

It will be up to voters to sort out whether such an array of goals is practical and affordable. What is certain is that little progress will be made on the problems those proposals address without at least a modicum of cooperation from the other side.

As the Democrats gear up for their celebration in Philadelphia, they are more united than Republicans, many of whom are still struggling to accept their party's choice of Trump. But Democrats have their own potential pitfalls. Friday's shootings in Munich are just the latest example of world events that play to the themes of fear and danger that Trump laid out.