Backers of a measure that would've legalized same-sex marriage in Illinois on Monday wrote a letter to advocates saying it's not the time for them "to splinter." It comes three days after the bill's sponsor, Democratic state Rep. Greg Harris of Chicago, decided not to call a House floor vote last week in the waning hours of the regular legislative session. But before adjourning, House Speaker Michael Madigan signed an extension on the bill, giving legislators until August 31 to pass it. If Gov. Pat Quinn, who supports gay marriage, calls leglislators for a special summer session, the bill could be voted on then.