Illinois Republican Senator Mark Kirk came out in support of marriage equality Tuesday shortly after the Supreme Court heard two potentially historic cases on gay rights.

"When I climbed the Capitol steps in January, I promised myself that I would return to the Senate with an open mind and greater respect for others," Kirk wrote on his blog.

"Same-sex couples should have the right to civil marriage. Our time on this earth is limited, I know that better than most. Life comes down to who you love and who loves you back-- government has no place in the middle."

Kirk is the second sitting Republican Senator to endorse marriage equality, following Ohio Republican Sen. Rob Portman last month.

The state senate in Illinois recently voted in favor of legalizing same-sex marriage in the state in a vote on Valentine's Day. Lawmakers in Illinois did not call the matter for a vote before they adjourned for their spring break.

Kirk, who voted to repeal Don't Ask Don't Tell, stated during a 2010 debate he supported civil unions.

"I oppose gay marriage and I support civil unions. But I also don't think we should have a federal takeover of all marriage law in the United States. I think the federal government is already trying to take over too much," Kirk said.

Kirk supported Illinois Republican party chairman Pat Brady when attempts were made to oust him after he announced his public support for the bill to allow gay marriage in Illinois.