WASHINGTON • President Joe Biden has gone on offense in recent days, attacking GOPers as extremists and MAGA Republicans posing an existential threat to democracy in the midterm elections.

Biden has taken the lead on his party’s messaging for the fall and will deliver a speech in Philadelphia on Thursday as he tries to tie the Republican Party and its voters to the singular figure of former President Donald Trump.

“The president thinks there is an extremist threat to our democracy,” White House press secretary Karine Jean-Pierre said in a preview of the speech’s content.

“The president has been clear on that particular piece. When we talk about a democracy, when we talk about our freedoms, the way he sees it is the MAGA Republicans are the most energized part of the Republican Party.”

Biden rolled out the phrase “ultra-MAGA” in May, a reference to Trump’s “Make America Great Again” campaign slogan and the result of six months of campaign research. But Trump and his supporters quickly embraced the pejorative.

Trump’s Save America PAC sent out fundraising calls featuring merchandise emblazoned with Trump as a MAGA Superman and embracing “ultra-MAGA” as a rallying cry.

“If loving your Country and wanting to put AMERICA FIRST makes you ULTRA MAGA, then yes. WE ARE ULTRA MAGA,” read one an email.

Thus, some GOPers compare Biden’s talking points to Hillary Clinton’s infamous “basket of deplorables” comment in 2016, saying they paint all conservatives as beyond reproach and are likely to backfire.

“Biden’s agenda has pitted neighbors against each other, rewarded the wealthy while punishing working families, and trampled on the rights and freedoms of Americans,” said Republican National Committee Chairwoman Ronna McDaniel.

“Joe Biden is the divider in chief and epitomizes the current state of the Democrat Party: one of divisiveness, disgust, and hostility towards half the country.”