Washington(CNN) GOP Rep. Doug Collins, one of President Donald Trump's top allies in Congress and an outspoken defender of the President, officially announced on Wednesday his campaign to run for Senate in Georgia, pitting him against Republican Sen. Kelly Loeffler.
Collins first made the announcement on Fox News' "Fox & Friends" before further explaining on Twitter that his presence in the Senate would "best benefit GA, the country and @realDonaldTrump."
The decision sets up a fierce melee for the November 2020 race. Democrats are attempting to pick up at least one of two US Senate seats up in Georgia this year as Republican Sen. David Perdue is also up for reelection in the state.
Collins' decision to run increases the chances that no candidate receives a majority of the vote, which would force a two-person runoff since all candidates -- Republican and Democrat -- face each other in the special election as part of Georgia's rules.
Republican groups allied with Senate Majority Leader Mitch McConnell are furious.
Steven Law, the president of the Senate Leadership Fund, called Collins "so selfish" and Loeffler a "warrior for the President." And Kevin McLaughlin, the executive director of the National Republican Senatorial Committee, said Collins' "shortsightedness" was "stunning." Both groups pledged to support the incumbent senator.
"All he has done is put two Senate seats, multiple House seats, and Georgia's 16 electoral votes in play," McLaughlin said. "The NRSC stands firmly behind Sen. Kelly Loeffler and urges anyone who wants to re-elect President Trump, hold the GOP senate majority, and stop socialism to do the same."
Collins pushed back on the NRSC's attack, saying his whole career has been about pushing "conservative ideas."
"That is just wrong," said Collins. "We are going to keep making our case. Believe me right now, there's nothing at risk."
Loeffler, a political newcomer who is also an Atlanta businesswoman and co-owner of the WNBA's Atlanta Dream, was appointed to the Senate last month by Georgia Republican Gov. Brian Kemp over Collins, who was Trump's preference. The appointment was made to fill the seat of Sen. Johnny Isakson, who retired last month due to health concerns.
Loeffler is married to New York Stock Exchange chairman Jeffrey Sprecher and has reportedly pledged to spend $20 million of her own money for her first political campaign. But Collins, a four-term congressman and chaplain in the Air Force Reserve who previously worked as a floor leader in the statehouse, has stronger ties to the base of the party in Georgia. Collins has also taken a high-profile role during the impeachment inquiry as the top Republican on the House Judiciary Committee.
His ubiquitous defense of Trump will attract Republicans and turn off some independent voters.
The President's praise could now determine which Republican advances. Meanwhile, Democrats say they have a better shot at taking the seat.
"At the start of this election cycle, Republicans believed they could take this state for granted, but not anymore," said Helen Kalla, spokesperson for the Democratic Senatorial Campaign Committee. "This expensive, protracted brawl -- already playing out on the front page -- will force unelected mega-donor Senator Loeffler and Trump ally Congressman Collins into a race to the right that reveals just how out-of-touch both are with Georgia voters."
This story has been updated with additional developments Wednesday.