SPRINGFIELD -- Republican U.S. Rep. Mark Kirk said Monday he wants to run for U.S. Senate and make Illinois' questionable ethical reputation a cornerstone of his campaign.

Kirk announced his intentions to run for the seat now held by Sen. Roland Burris and once held by President Barack Obama.

The seat was mired in controversy after former Gov. Rod Blagojevich appointed Burris to the post even after being arrested on corruption charges.

"We are the laughingstock state on the floor of the House of Representatives," Kirk said.

Kirk, of Highland Park, is a fifth-term congressman from the state's 10th district, north of Chicago. He works occasionally as a naval intelligence officer, returning from a stint in Afghanistan in January.

He'll be running in the February Republican primary election and has sometimes taken heat from within his own party for some of his views.

Recently, Kirk has come under fire from Republicans after voting for the Democrat-backed "cap-and-trade" proposal in Congress that seeks to control carbon dioxide emissions. He said he's heard a lot of feedback.

"I am absolutely listening," he said.

State Sen. Dan Rutherford of Chenoa is among the Republicans who have lined up behind Kirk early. Rutherford said he respects that Kirk comes to his decisions after a lot of thought, even if they don't always agree.

So far, Kirk at least will face retired judge Don Lowery of Dixon Springs in the Republican primary. And there's still time for more candidates to jump in.

Jabs from Giannoulias

Meanwhile, Kirk is already drawing jabs from Democrats. State Treasurer Alexi Giannoulias, a likely Democratic candidate for the same Senate seat, sought Monday to tie Kirk to former President George W. Bush's policies.

"It's a simple choice between the failed past or a promising future - a clear choice between the right course and the wrong one." Giannoulias said.

Kirk shot back, saying Giannoulias shouldn't assume he'll be the Democratic nominee.

"Right now, I think he should focus on his primary," Kirk said. "Don't count your chickens, there."

Kirk, 49, of Highland Park, says most of his extended family now lives in the Sullivan area, between Mattoon and Decatur.

He said he's planning a tour of the state to over the next couple months that includes a stop in Springfield Tuesday and an eventual stop at Blackburn College in Carlinville, where he went to school.