Former White House chief of staff Reince Priebus said Sunday the confirmation of Supreme Court Justice Brett Kavanaugh has stymied Democratic attempts to wrestle control of the Senate from the GOP.

“Something incredible has happened over the last couple of weeks, and that’s called the 'Kavanaugh effect' on Republican voters," Priebus said during an interview with "The Cats Roundtable" on AM 970 in New York, referring to how Kavanaugh has buoyed voter enthusiasm ahead of the 2018 midterm elections.

"The 'Kavanaugh effect' is you've basically shut out the Senate and now it depends on each individual House district how you communicate about the Kavanaugh situation," he said.

The party that will control the House is "a coin flip" given historical trends away from presidents during their first midterm elections while in office, added Priebus, who is the former chairman of the Republican National Committee.

[Related: Trump says rally crowds hint at a red wave: 'Something big is happening']

"The economy, as we started this conversation, is so strong, but thank-you votes in midterms usually don’t cut it," he said. "It’s usually something else that inspires the voter in a midterm.“

Democrats have to win 23 congressional districts to return to power in the House after the November elections.