Support for and opposition against gay marriage is nearly even in the U.S., but the issue divides Democrats much more than Republicans.
Numbers from the Pew Research Center shows that 46% of Americans oppose gay marriage, while 45% support legalization. However, 85% of "staunch conservatives" and 72% of "Main Street Republicans" oppose gay marriage, while Democratic groups are all over the map.
Only one of the core Democratic groups – Solid Liberals – favors gay marriage (85% to 13%), while most New Coalition Democrats and Hard-Pressed Democrats are opposed (51%-34% and 57%-32%, respectively). The Democratic-leaning Post-Moderns favor gay marriage by a wide 80%-14% margin, aligning themselves with Solid Liberals on this issue.
Broad majorities of both Staunch Conservatives (85% oppose) and Main Street Republicans (72% oppose) oppose gay marriage. By a less one-sided margin, more Disaffecteds also oppose (52%) than favor (34%) gay marriage. Libertarians are divided in their views; as many favor (43%) as oppose (45%) allowing gays and lesbians to marry legally.