Obama was for gay marriage in the 90s, ran for national office and changed his position only to civil unions. Went on Rick Warren's show and stated only civil union.
Once the country was in majority favor of gay marriage by 2011, Obama pivoted to being pro ssm for 2012.
It shows Obama is a savvy politician who understands incremental progress.
IIRC in 2004, the country was like 85-15 against ssm. By 2011 it turned into 52-48.
Donald to his credit has stated gay marriage is the law of the land, and he said it as President.