COLUMBUS, Ohio--A provocative new anti-Donald Trump TV ad from ex-U.S. Sen. Bill Bradley's new super PAC suggests that the GOP presidential nominee could start a nuclear war if elected.

Evoking Lyndon Johnson's infamous "Daisy" ad of 1964, the 30-second ad from the 52nd Street Fund, LLC, shows footage of nuclear tests while an announcer intones that "One nuclear bomb can kill a million people. That's more than all the men, women, and children living in Columbus, Ohio."

The ad then cuts to MSNBC's Chris Matthews telling Trump that "nobody wants to hear" about a presidential candidate possibly using nuclear weapons.

"Well, then why are we making them? Why do we make them?" Trump replied.

The ad concludes with the words "Be careful who you vote for" over a mushroom cloud.

Bradley's super PAC is spending $725,000 to air the ad in the Cincinnati, Columbus, and Toledo media markets, as well as in digital ads, according to a news release. The ad started airing on Monday for a week, according to a PAC spokesman.

"During these final days of the campaign, it's important to focus on the real stakes for America. Donald Trump's finger on the nuclear button is a horrifying prospect. His temperament and absence of experience makes him a danger to all Americans," Bradley said in a statement

The 52nd Street Fund is named after a line in the W.H. Auden poem "September 1 1939," the same poem used in the "Daisy" ad.

Antagonism between Bradley and Trump dates back decades. In 1986, Bradley sponsored a tax code overhaul that ended real-estate tax shelters. In 1999, as Bradley was seeking the Democratic presidential nomination, Trump penned an op-ed in the Wall Street Journal blasting Bradley and his tax reforms.

Trump wrote that Bradley, a Hall of Fame pro basketball player, "racked up a legislative record that is as embarrassing as his athletic record is impressive."

Even in a campaign where negative ads and attacks have been consistently lobbed at Trump, the ad, titled "Careful," stands out, said David Niven, an assistant political science professor at the University of Cincinnati.

The ad, Niven said, is clearly aimed at suburban women and others worried about security, and the parallels with the "Daisy" ad are also designed to win additional publicity in the media.

However, Niven added, he doesn't expect this ad will become as well-remembered as the "Daisy" ad, which only aired once.

"For a mushroom cloud ad, they really made this about as boring as they could," he said.

In a statement released by Trump's campaign, retired U.S. Army Lt. Gen. Michael Flynn said "Hillary Clinton and her dark-money special interest groups have recycled the 1964 'Daisy Ad,' which is the mother of all over-the-top negative ads and was so controversial it only aired for a very short time."

Flynn added: "Their desperation reinforces the fact that Hillary Clinton and her Washington insider friends are out of new ideas for our country, and view distortions and scare tactics as their only path to victory."