Ever since Donald Trump entered the race for the White House back in June, his Republican presidential rival Ted Cruz has kept any criticism of the boisterous businessman off the table.
But the amity between the firebrand Texas senator and the real estate mogul seems to be eroding, at least behind closed doors.
During a private fundraiser in New York City on Wednesday, Cruz questioned Trump's "judgment" to be president and deliberated on the mogul's "strength," two sources who attended the event told the New York Times.
For months Cruz and Trump have played nice with each other – or at least as nice as the two hard-hitting candidates know how to – with Cruz praising Trump for making immigration a focal point of his candidacy, while the magnate has hinted that if he gets the GOP nomination he would choose Cruz to be his running mate.
Publically at least – with the exception of Trump's proposed ban on Muslims entering the country – the two candidates are still very much in accord on the issues and continue to heap praise on each other. Both have centered their campaigns as counters to the so-called "Establishment" in Washington and preached hardline stances on matters like immigration and national security.
On the same day of the New York City fundraiser, Cruz made an appearance on Fox News saying he liked and respected Mr. Trump and "I don't anticipate that changing at all."
"The reason why I won't get engaged in personal insults and attacks, I don't think the American people care about a bunch of politicians bickering like schoolchildren," Cruz said. "I'm grateful Donald Trump is running."
The comments at the private event, however, appear to paint a different picture from a candidate who stands to be the biggest beneficiary of any loss of supporters for Trump. Cruz has been making gains on the front-runner Trump, pulling ahead of him in the latest Monmouth University in Iowa by five points and coming in second in Thursday's CBS/New York Times poll.
Yet another poll from Iowa released on Monday by CNN has Trump comfortably ahead in the Hawkeye state and most polls still have him with a double-digit lead nationally.
During the fundraiser, Cruz also lumped Trump in with fellow candidate, retired neurosurgeon Ben Carson.
"I don't believe either one of them is going to be our president," he said, adding that both Trump and Carson campaigns have a "natural arch" with gravity "pulling them down" now. Cruz did mention that Carson's descent has been much faster than Trump's.
"You look at Paris, you look at San Bernardino, it's given a seriousness to this race, that people are looking for: Who is prepared to be a commander in chief? Who understands the threats we face?" Cruz asked. "Who am I comfortable having their finger on the button? Now that's a question of strength, but it's also a question of judgment. And I think that is a question that is a challenging question for both of them."
Cruz's campaign on Thursday attempted to downplay the New York Times story, calling the newspaper's report of the Texas lawmaker criticizing Trump "misleading."
"In the course of a presidential election, the voters are going to make a decision about every candidate," Cruz said in a press release. "And ultimately the decision is, who has the right judgment and the right experience to serve as Commander in Chief? Every one of us who is running is being assessed by the voters under that metric, and that is exactly why we have a democratic election to make that determination."
Trump's communications director Hope Hicks told Fox News Latino that the campaign was not making a comment about Cruz's statement.