Some of the Democratic Party’s biggest guns, including former president Barack Obama, wheeled into firing position on the third night of the online convention.

Their target: Donald Trump.

But they were also there to stand, unified, with Joe Biden and his running mate, California Sen. Kamala Harris, who accepted the party’s nomination for vice president.

Obama, long a noted speaker, delivered an electrifying address, attacking Trump and his administration and extolling Biden’s character, empathy and fitness for the presidency.

Trump, he said, has “no interesting in using power to help anyone but himself and his friends.”

Worse, the former president said, under Trump “Democratic institutions are threatened like never before.”

“What we do these next 76 days will echo through generations to come.” — Former President Barack Obama

Obama’s speech was seen as less political and more patriotic, all but pleading with voters to rid the nation of Donald Trump.

In a late change to the program, Harris spoke briefly near the beginning of the evening, and at greater length near the end, accepting the nomination.

In her first appearance, apparently delivered backstage at an auditorium in Wilmington, she emphasized — as nearly every speaker did — the importance of voting. And she noted that President Trump and his allies seem intent on reducing that vote.

“Why don’t they want us to vote?” she asked. “The answer is that when we vote, things get better.” (See separate, related article about Harris’s acceptance speech, which climaxed the evening.)

The theme of the night was A More Perfect Union, a phrase from the preamble to the U.S. Constitution — and the title of a speech then-Sen. Barack Obama delivered during his victorious presidential run in 2008.

Obama spoke from the Museum of the American Revolution in Philadelphia, “a backdrop chosen to reinforce what the former president sees as the dire stakes of the moment,” reported the Associated Press.

Obama, who rarely uses bluntly critical language, minced no words about Trump.

Donald Trump hasn’t grown into the job because he can’t,” Obama said.

“I never expected that my successor would embrace my vision or continue my policies,” he said. “I did hope, for the sake of our country, that Donald Trump might show some interest in taking the job seriously. But he didn’t.

Obama also lavished praise on his former vice president.

“Twelve years ago, when I began my search for a vice president, I didn’t know I’d end up finding a brother,” he said. “Joe and I came from different places and different generations. But what I quickly came to admire about him is his resilience, born of too much struggle; his empathy, born of too much grief.”

Biden and Harris, Obama said, “actually care about every American — and they care about democracy.”

The evening was divided roughly into six sections, involving gun violence, climate change, immigration, families and violence against women, labor and the economy and child care. Each of several party luminaries spoke about one of these concerns.

They included House Speaker Nancy Pelosi; Massachusetts Sen. Elizabeth Warren; Wisconsin Gov. Tony Evers; New Mexico Gov. Michelle Lujan Grisham; former Rep. Gabrielle Giffords of Arizona — and Hillary Clinton, who won the popular vote in 2016 but lost to Donald Trump in the Electoral College.

“For four years, people have said to me, ‘I didn’t realize how dangerous [Trump] was,’ ‘I wish I could go back and do it over.’ Or worst, ‘I should have voted,’” Clinton said, adding:

Well, this can’t be another woulda coulda shoulda election.”