Washington (CNN) Nevada Sen. Dean Heller's Republican primary challenger is trying to tie him to Ivanka Trump as a way to cast him as too liberal.

Danny Tarkanian, in a local radio interview on Wednesday, invoked the first daughter's politics in an attempt to undercut Heller's claims of strong working relationships with President Donald Trump and Ivanka Trump.

"Dean Heller's saying that he talks to Trump on the phone all the time; talks to Ivanka Trump all the time," Tarkanian told KBET host Kevin Wall. "Well, Ivanka Trump was a Democrat, and she's very, very moderate to liberal, compared to the Republican base."

By casting the first daughter as out of touch with conservatives, Tarkanian demonstrated his effort to capture voters who bought into Trump's campaign pledges and are loyal to the President, but suspicious of those around him in Washington -- particularly on Capitol Hill.

The jab at Heller -- the nation's most endangered Republican senator in this year's midterm elections -- comes ahead of a June 12 primary, with the winner poised to face Democratic Rep. Jacky Rosen in November.

In an email, Tarkanian told CNN he "did not say nor mean to infer a relationship with Ivanka is a bad thing. It is a good thing. She is the daughter of the President."

"But," he added, "she is a registered Democrat and more moderate than the GOP base, which means her political views are probably similar to Heller's views, because he is a moderate to liberal." Ivanka Trump told CNN in 2016 that she is an independent who has always voted based on the candidate and not the party.

Heller's campaign didn't respond to a request for comment on Tarkanian's remarks.

Tarkanian's comments were reminiscent of former White House chief strategist Steve Bannon's own very thinly veiled jab at Ivanka Trump.

In December's Alabama Senate special election, Ivanka Trump reacted to the child molestation accusations against Republican Roy Moore by saying that "there is a special place in hell for people who prey on children." Three weeks later, her father endorsed Moore, saying he didn't believe the allegations. Bannon evoked that split on the eve of the election, telling Alabama Republicans that there is a "special place in hell for Republicans who should know better."

Still, the tactic seems at odds with the GOP electorate: Ivanka Trump is viewed favorably by 81% of Republicans, a January CNN poll found.

Tarkanian's argument that Heller has been insufficiently supportive of Trump is at the heart of his primary challenge.

And for months, it seemed like he had a point.

Heller, who endorsed Jeb Bush, then Marco Rubio, had been critical of Trump during the 2016 election. He skipped the Republican National Convention, then said weeks before the election that he was "99% against Trump" (though he'd say 10 months later that he voted for Trump after all).

Most famously, in a news conference with the national political world watching, Heller stood beside Republican Gov. Brian Sandoval and announced his opposition to an Obamacare repeal bill last summer, effectively sinking Trump's first health care effort.

Trump, in turn, embarrassed Heller at a White House meeting on health care. With the Nevada senator seated next to him, he predicted Heller would reverse his stance and vote for a new health care bill because "he wants to remain a senator, doesn't he?"

The personal animosity dissipated, though, when Trump, Heller and Reps. Kevin McCarthy of California and Mark Amodei of Nevada flew together on Air Force One to Las Vegas in October, in the wake of the mass shooting there.

On that flight, Trump and Heller had a long conversation and moved past their differences, several sources briefed on the matter said.

"They talked through their differences," said Michael McDonald, the Nevada GOP chairman. "Anything they had."

Heller discussed the plane ride himself at a news conference shortly after arriving in Las Vegas, saying he'd highlighted the work of first responders to the President.

"I had a rare occasion to be at 30,000 feet with a couple hours of face time with this particular president," Heller said then.

Heller later cozied up to Ivanka Trump as well, joining a group of Republican senators who dined at her Washington home last fall and working with her on several issues afterward.

Since then, Heller's votes have closely aligned with Trump's priorities.

His name was on a later version of the GOP's health care legislation. He was a staunch advocate for the tax bill that Trump signed into law in December. And Heller -- who voted for immigration reform in 2013 -- has voted against two compromise immigration efforts this year, but voted for Trump's plan.

Heller's recent loyalty to Trump appears to have paid off: At a recent Republican National Committee gathering in Washington, Trump told members at a closed-door meeting that he intended to visit Nevada to campaign for Heller ahead of the June GOP primary.

Tarkanian, the son of a legendary UNLV basketball coach, says he isn't buying any of it -- and doesn't believe Trump is, either.

"Since I got into the race, Heller has done everything he can to patch up his strained relationship with the President; however, I believe the President is too smart to buy it and is just appeasing Heller for his votes," Tarkanian said. "The President knows, as do Nevadans, that if Heller wins the primary, on June 13 he will be the same DC Dean, catering to the whims of moderates and Democrats in hopes of their votes in the general election."