McDonald is notable as one of four Republican members of the New York State Senate that voted in favor of the Marriage Equality Act in 2011.
[4] On June 16, 2011, McDonald spoke to the press on his intended support for New York State's upcoming vote on same-sex marriage.
In response to the pressure he was receiving from other Republicans to vote against the measure, he is quoted as saying: You get to the point where you evolve in your life where everything isn't black and white, good and bad, and you try to do the right thing.
[15] On April 4, 2012, Saratoga County Clerk Kathleen Marchione announced that she would challenge McDonald in a Republican primary in Senate District 43.
Andrew Cuomo, a Democrat, weighed in on the race by announcing his support for McDonald to continue his re-election bid on a third-party line.
[21] Following his primary defeat, McDonald opted to cease his campaign and throw his support to Marchione, stating that he was "very proud of [his] time in public service" and that "[s]tanding up for the communities [he] represented was always [his] first priority".
[22][23] Marchione went on to win the general election on November 6, 2012, defeating Democrat Robin Andrews and McDonald (who received 20,929 votes on the Independence Party line despite having suspended his campaign).