The MSNBC contributor and daughter of Sen. John McCain (R-Ariz.) is a longtime supporter of marriage equality. McCain joined Young Conservatives for the Freedom to Marry leadership in November 2012.
In May 2012, McCain questioned the sincerity of President Barack Obama's support for gay marriage. In an op-ed for the Daily Beast, McCain claimed that "talk was cheap during election season" and true support would include backing legislation to legalize same-sex marriage.
Shortly after Republican presidential candidate Mitt Romney lost to Obama, McCain said she would consider switching parties if the GOP failed to change some of its stances.
Last week, Sen. Rob Portman (R-Ohio) announced he had reversed his stance on gay marriage in response to his son, Will, coming out two years ago. Days later, former Secretary of State Hillary Clinton endorsed marriage equality in an announcement sponsored by the Human Rights Campaign, signaling the rise of politicians embracing America's growing support of gay marriage.