Donald Trump hit Twitter today to threaten a lawsuit over Sen. Ted Cruz’s (R-Texas) standing as a natural-born citizen.

“I would have won, in my opinion, if Carson wasn’t treated so badly by, you know, what happened with Cruz. I thought it was a disgrace, what they did to Ben Carson, who’s a really good man. I would have won in Iowa. And I did very well in Iowa,” Trump told Hannity on Thursday night.

Other than that, he steered clear of discussing Cruz throughout the interview.

The previous evening, Cruz touted his “incredible victory” in Iowa on Fox despite predictions that Trump “was unstoppable.”

“New Hampshire is a good state for a liberal Republican, New Hampshire is a good state for a Republican like Donald Trump who spent the first 60 years of his life describing himself as very, very pro-choice, supporting partial birth abortion. New Hampshire is a good state for a Republican like that,” Cruz said. “You know, Donald Trump is someone also who emphatically supported Barack Obama’s TARP bailout of Wall Street, emphatically supported Obama’s stimulus plan. And on healthcare, Donald Trump is calling for the same socialized medicine that Bernie Sanders is.”

The senator went on at length, comparing Sanders and Trump on healthcare and saying a vote for one was like a vote for the other.

In the Real Clear Politics polling average, Trump is 17 points ahead of Cruz, who is 6 points ahead of Sen. Marco Rubio (R-Fla.).

Trump hopped on Twitter to sling some arrows at his closest competitor. Cruz spokesman Rick Tyler retweeted some with the hashtag #Trumpertantrum:

Lying Cruz put out a statement, “Trump & Rubio are w/Obama on gay marriage.” Cruz is the worst liar, crazy or very dishonest. Perhaps all 3? — Donald J. Trump (@realDonaldTrump) February 12, 2016

How can Ted Cruz be an Evangelical Christian when he lies so much and is so dishonest? — Donald J. Trump (@realDonaldTrump) February 12, 2016

If @TedCruz doesn’t clean up his act, stop cheating, & doing negative ads, I have standing to sue him for not being a natural born citizen. — Donald J. Trump (@realDonaldTrump) February 12, 2016