U.S. Sen. Mark Kirk’s 16 year run in the U.S. Congress will come to an end come January. The incumbent Republican lost his reelection bid to U.S. Rep. Tammy Duckworth, a result that came to be inevitable following weeks of poor poll numbers and gaffes by the candidate.

But, as he conceded in front of a small room of supporters in Northbrook, Kirk was upbeat in congratulating Duckworth, and even invited her to a “beer summit” at the Billy Goat Tavern.

“This coming beer summit will show kids across Illinois that opponents can peacefully bury the hatchet after a tough election and that what unites us as Americans is much stronger than what divides us,” Kirk said.

Kirk spent a decade in the House of Representatives representing Illinois’s’ 10th District before running for and winning his Senate seat against former Illinois Treasurer Alexi Giannoulias in a Republican wave election.

An acknowledgement of Illinois’ blue state status, Kirk held positions that set him apart from the national Republican Party. He was the second GOP senator to support marriage equality, he is pro-choice and pro-gun control among other things.

Kirk was also one of the few GOP senators to completely disavow Republican presidential nominee Donald Trump, saying in June “I cannot and will not support my party’s nominee for President regardless of the political impact on my candidacy or the Republican Party.”

But, the position along with his socially liberal views put Kirk in a tough position with the Republican base, many of whom thought Kirk to be a “Republican in name only” (RINO).

Polls conducted earlier acknowledged the challenges facing Kirk in blue Illinois, but showed a winnable race. But episodes such as calling President Barack Obama the “drug dealer in chief” and comments about Tammy Duckworth’s ethnicity took their toll. And, Kirk, who had a stroke in 2012, has had to combat claims he’s not able to serve.

The Republican was also significantly outspent by his opponent, perhaps a product of the National Republican Senatorial Committee (NRSC) pulling their money out of the race in the early summer.