Will these attacks knock out Trump? His rivals hope so

What are some of the latest strategy for trying to take out Donald Trump?

GOP operatives at two super PACs have new advertisements in Iowa they think will make caucusgoers reconsider their support for the billionaire political superstar, who has remained popular in the presidential race here despite mounds of criticism. Rival presidential contenders have been taking shots at Trump, who sits atop the polls in Iowa, along with Texas U.S. Sen. Ted Cruz.

Here’s a summary of their attacks, which are circulating in Iowa a mere week before the first-in-the-nation vote here:

1. Trump has repeated called for a "terrific" health care system where “everybody’s going to be taken care of,” a system his rivals liken to the Democrat Bernie Sanders’ call for universal government health care coverage.

This is the angle in a new radio ad in Iowa paid for by the anti-Trump PAC called Make America Awesome. The ad will run in Iowa’s conservative 4th Congressional District, said the PAC's strategist Liz Mair, told The Des Moines Register.

“Remember, while some Trump defenders like to pretend that his support for single-payer is in the past, this is not true,” Mair said. “He advocated for a single-payer system and said he would institute one in his Sept. 13, 2015, interview with CBS News.”

2. Americans feeling a little broke could “use someone on our side, fighting for a better economy and higher wages,” says a second radio ad from Make America Awesome.

But Trump, the ad claims, has a history of “fighting for himself, not us” by “importing cheap foreign workers” and “using government power to seize private property.” His casinos “have slashed worker benefits,” the ad continues. “Trump got richer was at the expense of taxpayers, or the banks and investors who loaned him money,” the ad says.

This attack ad is running on KICD, KGLO, KMA, KOIL, KCPS and KBUR, Mair said.

3. Mailers landing in Iowa mailboxes ask: “How much do you know about Donald Trump and your taxes? After he became a candidate for president, Trump proposed the largest tax hike in history.”

This ad is from Our Principles PAC, an organization launched by GOP strategist Katie Packer. It cites Trump's book “The America We Deserve,” page 170.

4. Another mailer shows pictures of President Barack Obama, Democratic presidential candidate Hillary Clinton and Trump, and asks: “Which one of these three people said, ‘I believe in universal health care … it’s an entitlement to this country?’ Answer: Donald J. Trump.”

Calls from presidential candidates to repeal Obamacare generate big applause from conservative Iowa audiences, and this mailer questions whether Trump can be trusted to get rid of government-run health care.

5. Other than the attacks from by the newly formed outside groups, Trump is under fire from many other directions, including from Florida U.S. Sen. Marco Rubio, who says it's not enough to say "it'll be better, trust me"; from former Florida Gov. Jeb Bush, who argues Trump is "a jerk" and a bully who says his divisive and disparaging comments about women, war heroes, minorities and the disabled; from Kentucky U.S. Sen. Rand Paul who thinks Trump is power hungry and likens him to "Lord of the Rings" character Gollum, who just wants to possess the Ring of Power; and from Cruz, who has a television ad criticizing Trump for bulldozing "the home of an elderly widow for a limousine parking lot at this casino.”

Trump responded to some of the attacks — and fired off new ones — during his single Iowa event Sunday, in Muscatine.