The Senate Intelligence Committee has concluded that Republicans on the House Intelligence Committee were behind the leak of private text messages between the Senate panel’s top Democrat and a Russian-connected lawyer, according to two congressional officials briefed on the matter.

Senator Richard M. Burr of North Carolina, the committee’s Republican chairman, and Senator Mark Warner of Virginia, the top Democrat, were so perturbed by the leak that they demanded a rare meeting with Speaker Paul D. Ryan last month to inform him of their findings. They used the meeting with Mr. Ryan to raise broader concerns about the direction of the House Intelligence Committee under its chairman, Representative Devin Nunes of California, the officials said.

To the senators, who are overseeing what is effectively the last bipartisan investigation on Capitol Hill into Russia’s interference in the 2016 election, the leak was a serious breach of protocol and a partisan attack by one intelligence committee against the other.

The text messages were leaked just days after the same House Republicans had taken the extraordinary step of publicly releasing, over the objections of the F.B.I., a widely disputed memorandum based on sensitive government secrets. Taken together, the actions suggested a pattern of partisanship and unilateral action by the once-bipartisan House panel.

Fox News published the text messages, which were sent via a secure messaging application, in early February. President Trump and other Republicans loyal to him quickly jumped on the report to try to discredit Mr. Warner, suggesting that the senator was acting surreptitiously to try to talk with the former British spy who assembled a dossier of salacious claims about connections between Mr. Trump, his associates and Russia.

In dealing with incredibly sensitive material vital to the nation’s defense and safety, the committee has a responsibility to use that information for the greater good. To use it for a petty partisan squabble is way beyond foolish — it is downright dangerous.

Were this a Democrat, Republicans would be calling for that Democrats’ head. It is not a Democrat, however. It is a Republican and one whose values are increasingly in line with whatever Trump feels at a particular moment.

Nunes is compromised by his partisanship. He must step down or be forced to step down immediately. Not getting rid of his presence on this committee sends a clear message to other politicians and to either side’s base voters that this type of behavior is okay. We cannot tolerate this behavior, however, because of the nature of the intelligence committee’s job.

For all its talks about leaks, the White House and Fox News partnership was wonderfully happy to exploit this one.

And it’s not like anything big was leaked.

The Senate committee has conducted its investigation primarily in private, and Mr. Burr and Mr. Warner remained in lock step both publicly and privately. When Fox News published Mr. Warner’s text messages, for example, an aide to Mr. Burr told the network that he had been aware of Mr. Warner’s contacts with Mr. Waldman, and the two senators issued a joint statement condemning the leak.

Senator Marco Rubio, Republican of Florida and another member of the Intelligence Committee, also defended Mr. Warner.