When George W. Bush was running for president in 2000 as a new kind of Republican — the caring kind — he had a ready answer for those skeptical of his moderate views on immigration. “Family values do not stop at the Rio Grande,” he said, again and again. He was standing up for immigrants who come here seeking better lives for their children, and he repeated the message so often that it stuck.

Now, like so much else in Mr. Bush’s tattered slogan file, it’s in danger of coming unstuck. Negotiators struggling to draft an immigration bill in Washington are being pressured by the White House and Republican leaders to gut the provisions of the law that promote the unity of immigrant families in favor of strictly employment-based programs.

Details are still being sweated out in private, but a draft proposal circulated by the White House and the G.O.P. would eliminate or severely restrict whole categories of family-based immigration in favor of a system that would assign potential immigrants points based on age, skills, education, income and other factors. Citizens would no longer be able to sponsor siblings and children over 21, and their ability to bring in parents would be severely limited.

Unattached workers with advanced degrees and corporate sponsors could do all right, but not families, not the moms, pops, sons and daughters who open groceries and restaurants, who rebuild desolate neighborhoods and inspire America with their work ethic and commitment to one another. The plan would also shut out hundreds of thousands of people who have applied for family visas under current rules and are patiently waiting because of long backlogs.

The goal seems to be to end what immigration restrictionists call “chain migration,” a tendentious term that recasts in a sinister light one of the fundamental ways America was built, and a decades-old cornerstone of our immigration policy. It’s a cruel distortion that feeds fears of outsiders and fails to acknowledge that healthy immigration levels keep the economy running, particularly in a country with low unemployment and birth rates and workers who shun backbreaking, entry-level jobs.

America needs immigrants. Last year’s bipartisan Senate bill recognized this, and raised quotas for both family and employment-based immigration. Congress should do so again. Closing the door to families would be unjust and unworkable, and a mockery of the values that conservatives profess. It would only encourage illegality by forcing people to choose between their loved ones and the law.

Compromise is necessary with any bill, particularly on an issue as complex as immigration. But if a deal hews so closely to the new harsh line of the White House and G.O.P that it fundamentally distorts America’s pro-immigrant tradition, it would be better to ditch the whole thing and start over.