Another fighter has entered the Democratic rumble for the U.S. Senate seat in Pennsylvania.

Rep. Conor Lamb, D-Pa., announced on Friday he is entering the crowded Democratic primary, pursuing Senator Pat Toomey, R-Pa.’s, soon-to-be-vacated Senate seat.

The three-term congressman posted a video to Twitter announcing his campaign. He has been expected to announce a run for a while now.

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“Our democracy was born in Pennsylvania,” Lamb wrote on Twitter, sharing an ActBlue link. “I’m running for Senate because I believe Pennsylvania can save it.”

In the video, Lamb said he speaks with Pennsylvanians “who have come to believe that our democracy is in crisis” before claiming that “they’re right.”

“The other side denies reality and worships Trump,” the congressman claimed. “They’re making it harder to vote and lying about our elections.”

Lamb said he would be making his formal announcement later on Friday and that he deems the Pennsylvania seat “the most important Senate seat in the country.”

“We have to build on our majority and tell the truth to people about what’s really going on in people’s lives,” Lamb said, adding that the Senate needs to “raise pay for working people, protect retirements, and make sure you have health care when you need it.”

“All of these issues are on the line next year, and our opponents will lie about them, just like they lie about elections,” Lamb claimed.

“These are serious times, and we won’t win this race on Twitter,” Lamb said, adding that he and his campaign “plan to visit a dozen counties in the next week alone.”

National Republican Senatorial Committee (NRSC) spokeswoman Lizzie Litzow warned that Lamb will be a “rubber stamp” for liberal policies in the Senate and remarked that the Democrats are “already sprinting” as far as they can to the left of the aisle.

“Campaigns are marathons, but the Democrat candidates in Pennsylvania are already sprinting as far Left as possible, embracing Bernie Sanders’ agenda to ban fracking and destroy Pennsylvania energy jobs and agreeing with the Democrats’ reckless tax and spending spree,” Litzow said in a statement. “Conor Lamb is just another extreme progressive liberal joining the other extreme progressive liberals.”

“Lamb has voted 93% of the time with Nancy Pelosi and will be a rubber stamp for the dangerous liberal policies,” she continued, pledging that the “NRSC will spend every day highlighting their positions that are way out of step with the voters of Pennsylvania.”

Lamb has served in Congress since 2018 after defeating former Republican state Rep. Rick Saccone in a special election to replace former Rep. Tim Murphy, R-Pa., who had resigned from the House in October 2017.

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The Pennsylvania Senate race is expected to be the bellwether on which party will control the upper chamber in 2023.

Lamb is facing a robust Democratic primary for the Senate seat, where his opponents include Eric Orts, a business professor at the Wharton School of Business, and Lt. Gov. John Fetterman.

Fox News’ Chad Pergram contributed to this report.