Illinois Sen. Mark Kirk on Tuesday became the second Senate Republican to support marriage rights for same-sex couples, saying that "government has no place" in blocking loving marriages.

Kirk, in a statement released by his office, joined Ohio Sen. Rob Portman, R, in supporting gay and lesbian couples' right to marry. Portman announced his support for same-sex marriage following the public revelation that his son was gay.

"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," said Kirk, who missed almost a year on Capitol Hill after suffering a serious stroke.

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

Kirk's announcement comes amid a steady flow of Senate Democrats who have announced their support for same-sex marriage. Just seven Senate Democrats, who mostly hail from conservative or swing states, have yet to endorse marriage rights; in the past 24 hours alone, two Democratic senators -- Bob Casey of Pennsylvania and Tom Carper from Delaware -- have joined those ranks.

Republicans have been much slower to back same-sex marriage rights. Social conservatives and Christian leaders who oppose same-sex marriage figure much more prominently into GOP politics, making it more difficult for Republican lawmakers to break from the party's base.

Just this past weekend, for instance, Arizona GOP Rep. Matt Salmon reiterated his opposition to gay and lesbian marriages despite the fact that his son is gay.

Illinois, though, is a more reliably Democratic-leaning state, and Kirk has fashioned himself as a more moderate Republican throughout his career.