WASHINGTON — Some of their best friends turned out to be gay.

Or a daughter (Dick Cheney). Or a close pal (Jon M. Huntsman Jr.). Or a couple seated close by (the Maryland lawmaker Wade Kach).

President Obama’s embrace of same-sex marriage rights last week instantly touched off speculation about the possible political implications, but that misses a more nuanced point. Like so many other Americans in recent years, politicians are less influenced by party, faith or color on the question of favoring greater legal protections for gays, both liberals and conservatives say.

Instead, it’s more personal.

“If you don’t know anyone who’s gay, then it’s an alien lifestyle,” said Theodore Olson, the former solicitor general for President George W. Bush who supports same-sex marriage. But, he added, when “you realize that that’s Mary from down the street, she’s a lesbian and she’s with Sally, what would it be like if they couldn’t be together?” people come around.

During the civil rights movement, many white Northerners — including some who had never before interacted with black people — joined African-Americans to fight for the principle of equal rights, often opposing white Southerners who had lived among blacks all their lives yet saw nothing wrong with the separate but equal statutes. Principle seemed to come before the personal in many cases.