With Congress’ battered Democratic majority needing a base-energizing success to take into the fall elections — and with climate-change legislation stumbling badly out of the gate — party leaders suggested last week that they may bring immigration reform in from the cold this year after all.

It would be a good choice for Democrats. If a few Republicans can be persuaded to consider immigration reform on its merits — and not through the xenophobic lens of a noisy minority within their base — President Obama could score a legislative victory in a filibuster-free walk.

The evidence favoring immigration reform is stark in a way that ought to appeal to Republicans. A robust temporary-worker program would reduce illegal immigration and add billions of dollars in productivity to the U.S. economy.

Without immigration reform, the problem of illegal immigration will only grow worse as the U.S. labor market slowly recovers from the recession. The number of illegal immigrants in the United States has dropped to 11 million from its peak in 2007, but it will likely begin to grow again as demand for less-skilled workers picks up with the economy.

The economic and demographic realities that have fueled illegal immigration are still in place. In normal years, the U.S. economy produces hundreds of thousands of new jobs in retail, landscaping, food preparation and service, and home and commercial cleaning, all of which attract immigrants with limited job skills.

At the same time, the number of native-born Americans satisfied with such jobs continues to decline as the population becomes older and better-educated. The number of adult Americans without a high school diploma is expected to drop by another two to three million over the next decade. Yet our immigration system offers no means for a sufficient number of foreign-born workers to enter the country legally and fill that gap. So they enter illegally.

The key to reducing illegal immigration will be a strong temporary-worker program. This has been the missing ingredient of past efforts.

The 1986 Immigration Reform and Control Act legalized almost three million illegal immigrants. It also ramped up enforcement through increased border patrols and sanctions against those employing illegal workers. Yet it contained no provision for expanding legal immigration. Today, everybody agrees the act was a failure.

We know from experience that expanding opportunities for legal immigration can sharply reduce illegal immigration. In the 1950s, Congress dramatically expanded the number of temporary-worker visas through the Bracero Program. The result was a 95 percent drop in arrests at the border. If Mexican and Central American workers know they can enter the country legally to fill jobs, they will be far less likely to enter illegally.

A workable temporary-visa program would allow border agents to concentrate their efforts on intercepting real criminals and terrorists at the border. It would also reduce the temptation to hire illegal workers, in turn reducing the need to raid workplaces and impose national ID cards, employment verification systems, and other burdens on American citizens.

Allowing more legal workers to enter the country would also boost the productive capacity of our economy by allowing important sectors to expand, creating more middle-class employment opportunities for Americans. A 2009 Cato Institute study predicted that a sufficient temporary-worker program would boost the real income of U.S. households by $180 billion a year. A January study by the Center for American Progress came to a similar conclusion.

Enforcing a flawed immigration system has wasted tax dollars, frustrated the public, and created an underground labor force living in a legal twilight zone. The answer is comprehensive reform offering earned legalization to the millions of undocumented workers already here, temporary visas to new workers to meet our future labor needs, and sensible enforcement aimed at the remaining small minority that refuses to work within the new system.

The president and lawmakers from both parties need only look at the available data to find the path to effective immigration reform.