Supporters of a lax immigration policy love to hurl the charge of "Know-Nothingism" against their critics. But, oddly enough, it is the Senate immigration bill that duplicates a key element of the 19th-century Know-Nothing platform. Those long-ago nativists wanted to make immigrants wait 21 years to become citizens. The Senate bill effectively creates a comparable waiting period.

In Sunday's Democratic presidential debate, New Mexico Gov. Bill Richardson said it would take about 13 years under the bill to become a citizen -- as a kind of point of pride. President Bush, the compassionate conservative, brags about "the hurdles to citizenship" in the bill. They evidently want the "pathway to citizenship" to be as strewn with as many obstacles as possible.

They aren't motivated by animus toward immigrants, of course, but instead by fear and hatred of one word: amnesty. The Senate bill is piled with fines, fees and other requirements so its supporters can argue it's not really an amnesty. Amnesty, however, always has been considered any process whereby illegals immigrants become legal. The bill's drafters merely have created a conditional amnesty rather than an unconditional one.

The bill's supporters simply should say, "The vast majority of these illegal immigrants are people here to work, and they aren't going to be forced to go home; therefore there is no humane and moral option besides giving them an amnesty." That would be admirably straightforward and obviate the need for complex, obfuscatory lawmaking.

The bill gives pretty much every illegal alien here immediate legal status in the form of a probationary Z visa. That's the amnesty. Then come all the things meant to make the amnesty deniable: a $1,000 fine and $1,500 processing fee for an actual Z visa, which lasts four years; then, it has to be renewed for a $500 fee for another four years; after which, a green card is available with another $4,000 fine; and five years after that -- the possibility of applying for citizenship!

Some of the obstacles are clearly for show. Once someone has a Z visa, he has to go back to his home country to apply for a green card. This is pointless. The original purpose of this kind of "touch-back" provision was to make sure an illegal alien was home -- not here in this country -- when applying for legal status. Then, if his application was denied, he'd already be deported. But these green-card applicants will already have been legal for years and presumably back in the U.S. while their application is processed.

Cynical politics and economics play a role here. Republicans don't want formerly illegal immigrants voting anytime soon, since poor, low-skilled households aren't going to produce many GOP voters for a generation or so. And business doesn't care about citizenship one way or the other, as long as it gets its cheap labor. That's why employers support the indentured-servitude-style guest-worker program in the bill.

It is corrosive of American civic ideals to have widespread violation of the law and a class of people who aren't fully a part of American society. This bill -- which is neither soft nor tough enough -- will quickly return us to exactly that position. People who have absconded from deportation orders and aren't automatically eligible for the Z visas (some 600,000 people), illegals who have come here since January 2007 and are ineligible, and illegals who won't bother with the rigmarole of getting a real Z visa will form the basis of another large illegal population.

This is why a rational approach to immigration must start with enforcement. Only when enforcement is real would it be possible to give an amnesty to those illegals still here without repeating the experience of the past 20 years -- an ever-growing illegal population after an amnesty -- all over again. With a viable enforcement regime in place, illegals still here could get a path to citizenship more generous than the Know-Nothing version in the deeply flawed Senate bill.