While President Trump’s busy throwing himself a flashy, taxpayer-funded birthday blowout on Saturday in Washington, D.C., a totally different kind of party’s popping off across America — and spoiler, no cake, says one political activist … and No Kings.

That’s the theme of the “No Kings Day” protest event set for tomorrow … Ezra Levin joined us on “TMZ Live” to discuss the philosophy and the practical tactics of the coast-to-coast clapback at the Trump Administration’s exercises of power … and he’s crystal clear that the nationwide protest is all about peaceful people power under the Constitution.

Marches are scheduled Saturday in large cities and small towns across the country, in red states and blue … the overall event is meant as a firm demonstration in support of democracy and against monarchy — and a reminder to the president he’s not an absolute ruler.

Instead of packing D.C. with protesters and handing Trump a potential crackdown moment he might be craving, Ezra says they’re flipping the script — taking the protest everywhere else across the nation.

Levin’s in Philadelphia — site of the signing of the Declaration of Independence, of course — where he says as many as 80,000 people are expected to come out and march in the streets there. He tells us about training volunteers to deescalate dangerous confrontations with authorities, and how to “wage nonviolence” in a “joyful, peaceful display.”

As you know, public protests have erupted across the country in the past week — sometimes violently — in reaction to Immigration and Customs Enforcement raids targeting undocumented immigrants. In Los Angeles, Trump federalized thousands of California National Guard troops and called up 700 active-duty Marines to protect federal buildings — against the wishes of Mayor Karen Bass and Governor Gavin Newsom.