The chairman of the Senate Armed Services Committee put President-elect Donald J. Trump on notice Thursday that he would be a robust challenger to the new commander-in-chief by staging a committee hearing focused on Russian interference in the 2016 presidential election — the day before Congress makes the results of the election final.

“Every American should be alarmed by Russia’s attacks on our nation,” said Sen. John S. McCain III (R.-Ariz.), whose relationship with Trump has been difficult. The 2008 Republican nominee for president did not attend the Republican National Convention in Cleveland and has maintained a safe distance from the New York City developer as he ran for a new six-year term in the Senate.

Testifying in front of the committee during its open session were: James R. Clapper Jr., the director of national intelligence; Marcel J. Lettre II, the under secretary of defense for intelligence; and Adm. Michael S. Rogers, the commander of U.S. Cyber Command.

Without mentioning WikiLeaks, which posted stolen emails from the Democratic National Committee and John Podesta, the chairman of Hillary R. Clinton‘s presidential campaign, McCain alluded to the narrative that says that the Russians were behind the email theft and that they did so to help elect Trump.

McCain said he accepted as fact that the Russian government compromised emails from individuals and institutions, including political groups, and that the way they were made public was consistent with Russians methods and motivations. “‘These thefts and disclosures intended to interfere with the U.S. election process,” he said.

The three members of President Barack Obama‘s national security team issued a joint statement before taking questions. The statement fell short of the direct accusation that Russian President Vladimir Putin ordered the attacks on the DNC and/or Podesta; neither did the statement say directly that those attacks were by Russia. Rather, the statement said that Russia has done similar things elsewhere.

“We assess that only Russia’s senior-most officials could have authorized the recent election-focused data thefts and disclosures, based on the scope and sensitivity of the targets,” they said.

“Russia has also used cyber tactics and techniques to seek to influence public opinion across Europe and Eurasia,” they said. “In some cases, Russian intelligence actors have masqueraded as third parties, hiding behind false personas designed to misattribute the sources of the attacks.”

Nominally, the hearing “Foreign Cyber Threats to the United States,” was focused on threats from around the world, with emphasis on Russia, China, Iran, and terrorists. But Russia and its tampering in the election was all that was on the minds of the senators.

In one exchange with Clapper, Sen. Lindsey O. Graham (R.-S.C.) asked the DNI if he agreed that it was time to start getting heavy with the Russians, compared to the weak response by Obama.

“Espionage implies to me at least a passive collection, and this is much more active, so when it comes to espionage, we need to be careful of throwing rocks, but when it comes to interfering with an election, we need to be ready to throw rocks, right?”

Graham said,” I think that what Obama did is to throw a pebble.”

The South Carolinian compared the attacks to the NATO buildup in the Baltics along the Russian border.

“We are in a fight for our lives,” he said. “I just got back from the Baltics and Ukraine and Georgia, and if you think it is bad here, you ought to go there–and so, ladies and gentlemen, it is time now not to throw pebbles, but to throw rocks.”

The open hearing concluded its session for a lunch break with a second and classified briefing with the committee, where Clapper said he would reveal further analysis into the Russians’ methods and motivations, which he declined to discuss in the open hearing.

McCain’s next pushback at Trump could come Jan. 10, when the Senate Armed Services Committee hosts a hearing on civilian control of the armed forces, just as Trump’s nominee to take over the Pentagon, retired Marine Gen. James N. Mattis, needs a waiver from Congress. Federal law bars anyone from becoming the secretary of defense less than seven years after leaving uniformed service.