“That whole line of attack is unsavory to me,” said Sen. Lindsey Graham (R-S.C.). “I have no doubt that he’s loyal to the United States.”

National Republican Senatorial Chair Rick Scott (R-Fla.), who is neutral in the primary, said “I don’t have a concern about it” and Sen. Kevin Cramer (R-N.D.) said that “it’s a legit issue, but I think he’s answered it well. I don’t have any concerns about it myself.”

Cramer, who endorsed Oz on Monday, added that Oz’s negative remarks about Turkey’s authoritarian president have helped: “For a guy who has dual citizenship, he’s been critical of [Tayyip] Erdoğan, which I think probably inoculates him further.”

Despite Oz’s endorsement from Trump, he is still laboring to fend off rivals down the stretch. Oz narrowly leads his Republican primary foes in recent polls, but it’s clear that he doesn’t have the race put away — which means any edge he can get may be critical down the line, particularly as it pertains to the sensitive issue of his Turkish citizenship.

Oz says if he wins a Senate seat this fall, he will renounce his Turkish citizenship. He may find the seat harder to win in the interim if he’s the GOP nominee, though, should Democrats launch a new round of attacks on his ties to Turkey.

Senate Foreign Relations Chair Robert Menendez (D-N.J.), for example, thinks little of Oz’s plans to only scrap his citizenship if he wins the seat being vacated by retiring Sen. Pat Toomey (R-Pa.).

“Why then? Why not now? If you want to be a U.S. senator, you should tell the people of Pennsylvania that your only allegiance is to the United States,” Menendez said.

The citizenship drama reached the Senate several months ago, when it was reported that Oz may forgo seeking security clearances to maintain his Turkish passport. Sen. Dan Sullivan (R-Alaska), who supports McCormick in the primary, then held a press briefing arguing that members of the Senate “need full access” to intelligence.

Oz subsequently said he would renounce his Turkish citizenship if elected, arguing it was a “distraction” to his campaign.

In an interview on Tuesday, Sullivan said the fact that Oz is a dual citizen “was not my issue” in and of itself. “My issue was when he stated he would not do classified hearings.”

“You can’t do the job as a U.S. senator if that’s your view. So that’s where I was focused,” said Sullivan, adding that his concerns on that front are “alleviated, but it doesn’t change my mind of who would be a much better senator for the country.”

Another McCormick backer on the Hill, Sen. Bill Hagerty (R-Tenn.), said “I haven’t put any thought into” Oz’s citizenship. But McCormick and his allies have kept at it, with pro-McCormick group Honor Pennsylvania running an ad recently charging that after high school “Oz didn’t fight for America — he served for the Turkish Army instead.”

McCormick himself tweeted that Oz should “renounce your Turkish citizenship now. We won’t be fooled again.” In a March Fox News Radio interview, McCormick ridiculed attacks on his “patriotism from a guy who served in the Turkish military and is a dual citizen of Turkey, which is an adversary of ours in bed with Iran.”

Brittany Yanick, a spokesperson for Oz, said that the “these are pathetic and xenophobic attacks on Dr. Oz by David McCormick, who should be ashamed of himself.”

“There is no security issue whatsoever, and David McCormick knows that Dr. Oz has maintained his dual citizenship to make it easier to help care for his mother who has Alzheimer’s and lives there,” Yanick said.

But it’s not just McCormick lobbing criticism at Oz.

Alec Jones, campaign manager for fellow GOP Senate hopeful Carla Sands, Trump’s former ambassador to Denmark, said in a statement that “Oz’s loyalties are better suited for the Grand National Assembly of Turkey than for the United States Senate. He portrays himself as loyal to Donald Trump while campaigning in Pennsylvania, but he has a long and visible history of fawning over Turkish Dictator [Tayyip] Recep Erdoğan.”

Turkey’s presence in the Pennsylvania primary raises alarms among many Senate Republicans, who view Erdoğan critically. But they seem to give deference to Oz, who says he voted against Erdoğan in the 2018 Turkish election. It’s also possible Republicans are holding back because they don’t want to attack a potential future colleague in a must-win Senate race.

Summing up the views of many in the GOP conference, Sen. Joni Ernst (R-Iowa) asked rhetorically: “Is he a citizen of the United States?”

“Turkey gives me pause. I’m not going to say Dr. Oz gives me pause,” Ernst said.

Both Ernst and former Senate Intelligence Chair Richard Burr (R-N.C.) said, somewhat jokingly, that there are plenty of currently serving U.S. senators who they worry about having access to classified information. Burr said it was not a legitimate issue to raise in the primary campaign. While they participate in classified briefings on at least an occasional basis, senators are not subject to obtaining the same security clearances like certain senior staffers are.

Nonetheless, the toughest barrage came from Pompeo, a beloved figure among Senate Republicans. Ahead of a Trump rally for Oz last week, Pompeo pointedly criticized the candidate for voting in the 2018 Turkish election — a dramatic break between the former president and a onetime Cabinet secretary.

“Not only did he [Oz] not engage in the American political process, but he engaged in the Turkish political process. And that raises, in my mind, lots of judgments about his priorities,” Pompeo said.

Pompeo passed on running for a Senate seat in his native Kansas in 2020, much to the chagrin of a GOP conference that was struggling to hang onto a majority it ultimately lost that cycle. And many of them are now making clear that when it comes to Oz, they don’t share Pompeo’s concerns.

“I can’t imagine why anybody would be against [Oz] just because he maintains dual citizenship,” said Sen. Thom Tillis (R-N.C.).