President Bush says that Congress should pass comprehensive immigration reform "without amnesty," and he's right.

After all, it makes no sense to reward those who have broken the law while punishing those who have obeyed it.

Unfortunately, the proposal the Bush administration recently floated contains a new "Z-Visa" category that would grant amnesty to any illegal immigrant willing to pay a modest fee.

Bush says his proposal would:

- Secure U.S. borders.

- Give employers the tools necessary to verify the immigration status of hires.

- Provide a "Y-visa" for temporary workers.

- Provide a "Z-visa" for aliens who are working illegally in the U.S.

- Require English proficiency.

- Simplify immigration law.

Four of these are no-brainers. Securing the border, simplifying immigration law and giving employers enhanced tools to verify the immigration status of hires are concepts that enjoy widespread support.

Requiring English proficiency is controversial with some Hispanic groups, but it's extremely popular with the voting public.

Yet the new Y- and Z-visa categories could prove to be very complicated and may provide a pathway to citizenship for the illegal aliens in the country, as well as millions of potential new immigrants living outside the U.S. who may apply for admission through one of these new visa categories.

Amnesty, though, is simply unacceptable. The Senate is expected to begin a historic debate on immigration reform next month, and there's a danger that enough Republicans and Democrats may team up to provide Z-visas to the estimated 12 million illegal immigrants in the country today.

In addition, the president's proposal contains a new temporary-worker program that would provide Y-visas to temporary workers, with a numerical cap adjustable by the secretary of homeland security.

Y-Visa holders would have to choose one of two temporary programs that would allow them to remain for either two years or nine months. Then they would return home for six or three months, depending on the visa.

This program is similar to legislation previously proposed by Rep. Mike Pence, R-Ind., and Sen. Kay Bailey Hutchison, R-Tex.

Under their plans, the visa would be limited to the worker and wouldn't allow spouses or family members access to the United States. These Y-Visa holders could apply for a green card and be eligible for emergency social services.

President Bush's new Z-visas go further, though. Too far.

They would provide a completely new category of visa for illegal workers who are currently employed, have a working head of household or are in school for most of each year.

This new visa category ought to be renamed "Amnesty Visas," because they would provide visas to illegal aliens (and their families) who work in the United States today.

With Z-visas, illegal aliens need pay only, every three years, a $2,000 fine and then a $1,500 fee to be allowed to remain in the U.S.

And if an illegal could provide evidence that he or she had met certain assimilation standards, the fees would be cut even further.

The administration claims that the $3,500 in fees to be paid every three years would amount to "large penalties."

That's why Bush can claim his plan differentiates "between amnesty and restitution."

Yet in real life, these fines are nothing more than a slap on the wrist, after which the federal government forgives aliens for what in many cases amounts to years of illegal residence in the United States.

Conservatives should fight any form of "Z-visa."

Americans understand it would be nearly impossible to assimilate 12 million Z-visa holders into our society in a short period of time. Worse, Z-visas would weaken national security, because it would be difficult for our federal government to conduct background checks on millions of visa holders.

Our nation of "laws, not men" must uphold those laws - not find ways to circumvent them. If lawmakers want to craft a true temporary worker program, they should go ahead and do so. Then they'll need to convince voters that they've designed the correct approach to the illegal immigration crisis.

The president's Z-visa category, though, is the wrong approach. Policymakers should give it no quarter.

Brian Darling is director of U.S. Senate relations at The Heritage Foundation, a leading Washington-based public policy institution.