By Ted Barrett, CNN Senior Congressional Producer
(CNN) - The Senate is to vote later Tuesday to begin debate on immigration reform, an emotionally charged proposal with huge political stakes that may never get through Congress despite years of negotiation and major compromise.
It aims to create a 13-year path to citizenship for most of the country's 11 million undocumented immigrants, a bipartisan proposal hammered out by the so-called "Gang of Eight" senators this spring that has the backing of President Barack Obama.
Polls show many Americans also favor some form of immigration policy overhaul, depending on the details of legislation.
GOP leaders have signaled their support for starting debate, so a procedural motion aimed at doing so is expected to receive the 60 votes necessary to take that next step even if the fate of the legislation is uncertain.
Obama and congressional Democrats are anxious to fulfill a long-delayed pledge to Latino voters to pass reforms to the troubled immigration system. Passage could pay political dividends for their party for many years.
Republicans are in a more difficult bind.
Latinos backed Obama over Mitt Romney by a 44-point margin in November and GOP strategists are concerned about the party's long term viability in national elections if that trend is not reversed.
Some congressional conservatives say opposing the "Gang of Eight" plan is a matter of principle and they won't bend. They remain skeptical about any measure offering a path to citizenship. A lot of them consider it amnesty.FULL STORY