DENVER >> A Colorado congressman who questioned the citizenship of President Barack Obama expanded on his apology Thursday, calling his comments at a GOP fundraiser this month “inappropriate and boneheaded.”

Rep. Mike Coffman said in an op-ed column published Thursday in the Denver Post that he “should never have questioned the president’s devotion to our country. The president and I disagree on many issues — his approach to health care, jobs and energy independence, to name a few. But disagreeing on these issues was not license for me to question his devotion to our country.”

Earlier this month, the Republican congressman said at an Elbert County event that he doesn’t know if Obama was born in the United States and that in his heart, Obama is not an American.

Coffman’s remarks echoed a long-simmering political controversy generated by those who say that Obama was not born in the U.S. and therefore is ineligible to hold the nation’s highest office. The Obama administration attempted a year ago to dismiss the conflict by releasing his long-form birth certificate showing that he was born in Hawaii.

Coffman faced intense criticism after a recording of his comments was released to the media. He released a short statement apologizing for the remark before he wrote the newspaper column.

It’s too soon to say what the long mea culpa from the two-term congressman will mean for his re-election bid in a suburban Denver district that has become much more competitive for Democrats because of redistricting. Coffman rolled up big wins in his first two contests for the suburban Denver district, carrying roughly two-thirds of the vote against a little-known Democrat with no political experience two years ago.

But Coffman faces a dramatically different landscape this year because of congressional redistricting. Coffman’s turf now is divided roughly evenly among Democrats, Republicans and independents. Colorado’s 6th Congressional District will soon include the entire city of Aurora, a one-time Republican stronghold trending toward Democrats.

Coffman will no longer represent the most conservative parts of his current district, including Elbert County, where Coffman questioned Obama’s citizenship earlier this month.

In the op-ed, the congressman called questions about Obama’s citizenship a “distraction.”

“I have never been afraid to admit when I am wrong, and I was wrong here,” Coffman wrote.

Democrats have seized on Coffman’s remark as evidence he’s too conservative for the district. Coffman’s Democratic challenger, state Rep. Joe Miklosi, said Coffman’s remark was “a comment you would normally hear from Rush Limbaugh.”

Questions about Obama’s citizenship persist among some Republicans, though GOP leadership and presumptive presidential nominee Mitt Romney have denounced theories. In Arizona, Secretary of State Ken Bennett said last week that he may refuse to put the president on the ballot in November unless the state of Hawaii authenticated Obama’s birth certificate. On Wednesday, Bennett said in a statement that his office received the necessary information needed to put the matter to rest.

Coffman did not immediately return a call Thursday from The Associated Press. He had no public events scheduled this week, and Coffman repeatedly declined to elaborate when a reporter asked him about the remark on the street.