This has been a good year for gay rights advocates — with public opinion shifting in their favor and same-sex marriage advancing in the states — but not when it comes to immigration.

An 844-page bill introduced in the Senate in mid-April by a bipartisan group of eight lawmakers includes measures to make legal immigration easier for highly skilled immigrants, migrant farmworkers and those living here illegally. It has no provisions that would help foreigners who are same-sex partners of American citizens to become legal permanent residents.

Gay advocates were sharply disappointed to find that same-sex couples were excluded from the legislation, since the Democrats who wrote it included two of their most consistent champions, Senators Charles E. Schumer of New York and Richard J. Durbin of Illinois, the second highest-ranking Senate Democrat. Senator Patrick J. Leahy of Vermont, the Democrat who is chairman of the Judiciary Committee, where the bill is under consideration, has offered, since as far back as 2003, a separate measure that would allow immigrants in long-term same-sex relationships to obtain residency with a green card.

But in the lengthy closed-door negotiations that produced the overhaul proposal, the four Republicans in the bipartisan group made it clear early on that they did not want to include such a hot-button issue in a bill that would be a challenge to sell to their party even without it, according to Senate staff members. The Republicans are Lindsey Graham of South Carolina, Jeff Flake and John McCain of Arizona, and Marco Rubio of Florida.