President Trump is sufficiently pleased with the new immigration bill sponsored by Republican Sens. Tom Cotton and David Perdue that he didn't just endorse it but made an appearance with them to promote it. "The RAISE Act," he said, "will reduce poverty, increase wages, and save taxpayers billions and billions of dollars."

And the bill does contain good ideas. Regrettably, however, these are likely to be obscured by the policy that will make the biggest headlines, a 50 percent reduction in legal immigration. There is no problem at the moment with excessively high levels of legal immigration. It is not the overall number of immigrants but the composition of the whole, with too many low-skilled newcomers and too few high-skilled ones that is the problem. The bill seeks to fix that problem and should do so, which makes its effort to stanch the flow of arrivals overall both redundant and, in all likelihood, counterproductive.

Another problem with the bill is that it also arbitrarily halves the number of refugees that America will take in. The "extreme vetting" of refugees that Trump has talked about is perfectly appropriate. But a limit of 50,000 refugees doesn't take into account the number of people who might actually need refuge from tyranny or religious persecution in any given year. Which Yazidi, Christian, or Shiite survivor of ISIS genocide, will be the first turned away and told, "Sorry, but we've reached our annual limit, try again next year"?

It is unfortunate that these caveats must be entered because they mar salutary and smart elements of the bill that focus on fixing and not just shrinking the lawful immigration system. We have long supported a skill-based system that prioritizes attracting the best and brightest to America, and even if this bill can't pass in its current form, we hope Congress will amend it and adopt such a system.

The needs of the nation should always be the rationale of immigration policy. Outside the question of legitimate asylum-seekers and refugees who need our help and have a moral claim upon it, the normal immigration process should be designed not to simply bring in people who feel America can help them flourish but to bring in people who will make America flourish.

From the founding of the original colonies in the 17th century, America has permitted and encouraged immigration but never for immigrants' sake. It has encouraged their entry for the good of the nation, according to the needs of the times. The open door of yesteryear was not purely an act of altruism, as some characteristically tendentious cable news reporting on Wednesday sought to suggest. Immigrants have in each era breathed new life into their new homeland, and that was at the core of why they were welcome. Immigration policy should continue in that tradition, consistent with the needs of the host nation, refreshing the nation's bloodstream with those most eager to come and embrace the American values of liberalism, toleration and self-reliance.

RAISE's sharp reduction of legal immigration is likely to hinder this goal. It is also probably superfluous. If Congress approves a system by which more educated and skilled foreigners can immigrate, then the strict numerical limits in this bill won't be necessary. Instead of merely reducing the number of non-employment visas, this bill should be replacing them with a corresponding increase in visas that would be awarded under the skill-based system. RAISE thus aims to set up a better system to attract the world's brightest, but would then fail to exploit it properly.

There is no need to ratchet down legal immigration when a simple refocus of the immigration system on skill would by itself fulfill most of the president's promises on this issue. It would ease downward pressure on wages that mass economic migration currently causes for the working class. It would probably even help unskilled workers by expanding their job opportunities, as a growing pool of professionals and entrepreneurs will require a larger pool of low-skilled workers to support their ventures. And a system that prioritizes skilled immigration also is far less likely to attract any significant number of violent criminals or people who will become a burden on the welfare state.

In short, there's something substantial to work with in the bill that Cotton and Perdue have put forward. If Congress embraces a merit-based system and changes the focus of immigration reform to something more practical, oriented toward solving existing problems, it can make immigration great again.