There's no reason why Democrats would want to kill this bill.
If it does die, they're going to revive it-just like the DREAM Act-but there's no way they'll pass up a chance to enfranchise millions of future statist, dependent Democrats.
That's what I assume. So, with a homo amendment, I don't understand what votes Leahy would pick up that he doesn't already have. It just seems to me he's taking a bill that's dodgy for Dems in conservative districts and making it downright radioactive. A mystery.