Eric Reyes, a Democrat-turned-independent-turned-Republican, withdrew this week from the 17th Congressional District race.
He was challenging former U.S. Rep. Bobby Schilling, R-Colona, in the March 18 Republican primary in the district that includes Whiteside and Carroll counties.
They were vying to run against first-term Rep. Cheri Bustos, D-East Moline, in the November general election.
In a news release, Reyes, a Rock Island attorney, said Republicans needed to unite in their efforts against Bustos.
"Rather than continue to divide the party and waste precious time and resources of all involved, I have chosen to withdraw my candidacy and focus on advancing the principles of freedom, liberty and limited constitutional government," he said in a statement.
In an interview Thursday, Reyes said he planned to vote for Schilling, who lost his seat in 2012 to Bustos after 2 years in office.
Recently, a couple of Schilling's contributors challenged Reyes' election petition in an attempt to remove him from the ballot
"No matter what happened, the challenge would have just dragged on and on," Reyes said in the interview. "I didn't have the time or money to fight it. I believe in the principles of the Republican Party."
In the past couple of years, Reyes has undergone a significant political evolution. He announced in the fall of 2011 that he would run as a Democrat for the congressional seat. But in December of that year, he revealed that he would, instead, file as a write-in independent candidate. He did, but received only a small fraction of the vote.
In a district redrawn by state legislative Democrats, Bustos won 53 percent of the vote to beat incumbent Schilling.
Last year, Reyes announced he would run as a Republican in the 17th District. In switching parties, he said he had always believed in the core principles of the GOP. In 2011, though, he spoke favorably of the Affordable Care Act, known as Obamacare, which a great majority of Republicans oppose.
As a Republican, Reyes supported legalized marijuana and same-sex marriage, which most in his new party oppose.