Senate Majority Leader Mitch McConnell (R-Ky.), flanked by Sen. John Thune (R-S.D.), left, and Senate Majority Whip John Cornyn (R-Tex.) speaks with reporters at the Capitol on Feb. 27. (J. Scott Applewhite/AP)

A former chief of staff to President Barack Obama said Sunday that the Senate’s top Republican insisted that a bipartisan appeal for states to step up election security in the face of Russian aggression be “dramatically watered down” before it was issued in advance of the 2016 election.

Denis McDonough said on NBC’s “Meet the Press” that Senate Majority Leader Mitch McConnell (R-Ky.) was single-handedly responsible for downgrading the language in a letter “asking the states to work with us” to better secure election systems in light of intelligence indicating Russia was attempting to interfere in the election. McDonough complained that members of Congress have shown a “stunning lack of urgency about this question,” and he put the blame mostly on Republican leaders in Congress.

“The lack of urgency that we saw from the Republican leadership in 2016, we continue to see to this day today,” he said. “It’s beyond time for Congress to work with the administration, to work with the states, to ensure that our electoral systems are ready to go. This is not a game.”

McConnell spokesman Don Stewart accused McDonough on Sunday of having a selective memory. At the time, Stewart pointed out, the administration did not want to publicize the Russia connection, and McDonough even wrote in a Washington Post op-ed that he had asked Democrats to avoid calling out Russia publicly “mainly to avoid politicizing the issue.”

“Give me a break,” Stewart added.

The exchange highlights a testy ongoing standoff between Democratic and Republican lawmakers presently at odds over who should be held responsible for Russian interference in the election: Obama, who was president at the time, or President Trump. The intelligence community has concluded that the Russian interference had been aimed at aiding Trump’s campaign.

The partisan dispute has prompted the breakdown of at least one investigation on Capitol Hill, where three committees are probing allegations of Russian interference in the election.

Republicans on the House Intelligence Committee put some of their accusations against the Obama administration into a recently publicized memo charging that federal law enforcement agencies based a request to conduct surveillance against former Trump campaign adviser Carter Page on faulty information paid for by the Democratic National Committee and the Hillary Clinton campaign. The source of that information, ex-British spy Christopher Steele, had been compiling information that he filed in a now-infamous dossier alleging that Trump has personal and financial ties to Russian officials.

Democrats on that panel spent much of the past month rebutting the GOP’s claims and attempting to show through a memo of their own that federal law enforcement agencies had not only acted properly, but also that there was ample reason to suspect that Page and other Trump affiliates’ interactions with Russians were suspicious.

Not one congressional panel looking into the Russia probe has released a bipartisan plan for how to strengthen election security, even though the 2018 primary season begins in certain states this month. The Senate Intelligence Committee, which is also investigating Russian intervention, is expected to release recommendations later this month, though that will not mark the end of its probe.

In the House, meanwhile, lawmakers are expecting that the GOP majority will soon wrap up the intelligence panel’s investigation of Russian interference — allowing members to better focus on exploring how Obama’s Justice Department handled investigations of a slew of matters, including the Clinton email probe and a 2010 uranium deal that let Russia assume a controlling stake in a company operating in the United States.

Several Republican lawmakers have suggested that those matters require a second special counsel to examine them. On Sunday, Rep. Trey Gowdy (R-S.C.), the outgoing chairman of the House Oversight and Government Reform Committee, seemed to inch toward joining their ranks.

“I think we’re trending perhaps towards another special counsel,” Gowdy, who is also a member of the House Intelligence Committee, said on Fox News.