US President George W. Bush faces a major rebellion within his own party if he follows through on a promise to push legislation that would offer millions of illegal immigrants a path to US citizenship.
Almost no issue divides Republicans as deeply.
To get the guest-worker initiative through Congress, Bush will need to go against the wishes of many Republicans and forge bipartisan alliances. That's what President Bill Clinton did in 1993 to win approval for a free trade agreement with Mexico and Canada, over the objections of a large bloc of congressional Democrats.
The chance seems slim for finding common ground between those in favor of liberalized immigration laws -- Bush, Republican Senator John McCain of Arizona, and California Governor Arnold Schwarzenegger for example -- and those who want fewer immigrants, tougher border controls and harsher penalties.
Opposition is strongest among House Republicans.
"In our party, this is a deep division that is growing deeper every minute," says Republican Representative Tom Tancredo of Colorado. He heads a group of 70 lawmakers who are against easing immigration laws.
Tancredo said Bush's guest-worker proposal is "a pig with lipstick" and will not pass.
Bush asserts that he won valuable "political capital" in the election and intends to spend it. It is not clear how much of that he is willing to spend on the immigration measure.
Higher on his list of priorities is overhauling the Social Security system, rewriting the tax laws, limiting lawsuit judgments and making his first-term tax cuts permanent.
An estimated 10 million immigrants live in the US illegally; the vast majority are from Mexico, with an additional million arriving every year.
A hint of the trouble ahead for Bush on immigration came this month when proposals to tighten -- not ease -- border restrictions nearly undermined a bill to restructure US intelligence agencies.
The chairman of the House Judiciary Committee wanted the measure to bar states from giving a driver's license to illegal immigrants. Republican Representative James Sensenbrenner of Wisconsin said some of the Sept. 11 hijackers gained access to US aircraft by using a driver's license as identification.
Sensenbrenner ultimately backed down, but only after House Speaker Dennis Hastert promised that the chairman's proposal would be considered in separate legislation next year.
The president's plan would grant temporary-worker status, for three years to six years, to millions of undocumented workers. It also would make it easier for those workers to get permanent US citizenship.
As governor of Texas, Bush was committed to immigration changes. As president, he came close to making a deal with Mexican President Vicente Fox in the days before the attacks of Sept. 11, 2001. Those plans were put on hold as tighter borders took on a higher priority for the US.
As a presidential candidate, both in 2000 and this year, Bush eagerly courted Hispanics, the fastest-growing ethnic group in the electorate.
"We will keep working to make this nation a welcoming place for Hispanic people, a land of opportunity para todos [for all] who live here in America," Bush told the League of United Latin American Citizens last summer.