President Bush finally re-entered the immigration debate last week to appeal for civility and compassion. He's way late. The debate is already bitter and divisive, especially within the Republican Party, and it's only getting worse.

More than 200 House Republicans are on record as favoring a draconian measure that would make it a felony simply to be in the United States illegally, or to offer assistance -- even a meal or counseling -- to an illegal immigrant.

Meanwhile, immigrant-rights groups are staging huge protests. Roman Catholic bishops have denounced the legislation. Leading Democrats are vowing to filibuster a slightly less punitive measure from Senate Majority Leader Bill Frist if he brings it to the floor. A Frist aide said, "Go for it!"

Bush has allowed the situation to get out of hand. Since before he became president, he has favored a moderate approach to immigration -- enhanced border security combined with work permits for new entrants and for those presently working illegally.

But Bush failed to push this approach, and now his party is split between fellow moderates -- led by presidential hopeful Sen. John McCain, R-Ariz. -- and restrictionists led by another presidential aspirant, Rep. Tom Tancredo, R-Colo.

If ever a situation cried out for reason, bipartisanship and presidential leadership, it's this one.

The most sensible proposal is sponsored by McCain and Sen. Edward Kennedy, D-Mass. It involves enhanced border security, tighter controls on employment of illegal immigrants, a permit program and a way for many of the 12 million illegals here now to earn their citizenship.

Restrictionists have it right that U.S. borders are scandalously porous, with up to 10,000 persons crossing each day, or 3 million a year.

Building a 700-mile wall along the Mexican border, as provided in the House bill, would be a terrible symbol for a country proud of the Statue of Liberty, but the goal of U.S. policy should be the equivalent -- sealing the border to illegal entry as much as possible.

In fact, that's embodied in the McCain-Kennedy bill and administration proposals, with increases in personnel and technology for Customs and Border Protection, and by expansion of border detention facilities.

The sticking point between the sides is what to do about the estimated 12 million people currently living illegally in the U.S. Restrictionists want them to leave -- and, in the process, discourage others from coming.

But the McCain-Kennedy approach is "earned legalization," whereby illegals would have to have a record of employment, pay $2,000 in fines, learn English, pay taxes, have a clean record and wait behind all who have applied to enter the country legally. Bush's allies at the U.S. Chamber of Commerce and the industries that disproportionately employ immigrants -- agriculture, home-building, hospitality -- favor "earned citizenship."

Polls suggest that the public is massively confused and ambivalent about immigration. A Quinnipiac University survey last month found that 54 percent of voters want to make it harder for illegal immigrants to work in the U.S. legally. But a Time magazine poll showed that 76 percent favor earned legalization.

This is a moment for presidential leadership. Bush has limited political capital left, but social peace is a cause worth spending it on.

(Kondracke is executive editor of Roll Call, the newspaper of Capitol Hill.)