We need to offer undocumented workers a legal path toward citizenship.

If you’re concerned about the economy, you should be in favor of this approach.

According to a recent study conducted by UCLA researcher Raul Hinojosa-Ojeda, the legalization of the nation’s estimated 12 million undocumented workers will raise wages, increase consumption, create new jobs and generate new tax revenue. Furthermore, it would raise the wage floor for native-born workers and naturalized immigrants alike.

All told, legalization would add about $1.5 trillion to the U.S gross domestic product over the next 10 years. It’s a ready-made economic stimulus plan.

Another recent study, this one by the Fiscal Policy Institute, examines the impact of immigrant workers on the economies of the 25 largest metropolitan areas in the United States, collectively responsible for half of the country’s total GDP. These cities contain 66 percent of the nation’s immigrant population overall and a majority of the estimated 12 million undocumented workers. The findings show that between 1990 and 2006, the fastest growing of these economies were also those with the largest increase of immigrant workers. These migrants are young, eager to work and highly productive.

By contrast, maintaining the enforcement-only approach drains the economy. The budget for Immigration and Customs Enforcement (ICE) has increased 82 percent in only six years, growing from $3.3 billion to $5.9 billion and counting. The burdensome cost of enforcement-only policies extends into the legal system, as large numbers of immigrant workers continue to be rounded up, crowded into detention centers and jamming the federal courts.

According to ICE estimates, 442,000 immigrants were incarcerated in 2009. This represents a doubling of the rate since 2003, with most detainees charged with only minor immigration violations.

At the state and local level, the costs of enforcement-only tactics are also sopping up resources, at a time when state governments are dealing with crippling budgetary shortfalls.

Keeping millions of productive workers in the shadows and off government records is costly, has failed to curtail immigration, lowers the wage threshold for all workers and minimizes immigrant contributions to the economy.

As then Department of Homeland Security Secretary Michael Chertoff admitted in 2006, “When you try to fight economic reality, it is at best an expensive and very, very difficult process and almost always doomed to failure.”

So why continue with this failed strategy?

During his recent State of the Union address, President Obama acknowledged that immigrants “contribute to our economy and enrich our nation.”

But we need more than words; we need action.

Let’s move forward with real immigration reform immediately.

Justin Akers Chacon is a professor of U.S. History and Chicano Studies in San Diego. He can be reached at pmproj [at] progressive [dot] org.