President Trump had the crowd roaring at his rally in Green Bay last month over his jabs at Democrats for opposing his immigration agenda. He proclaimed how quickly the immigration system could be fixed if only Democrats joined his side.

“I used to say in 45 minutes. It’s really 15 minutes. It’s so simple, but we need Democrats to vote on it. Otherwise we can’t change it,” Trump said.

But all the Democratic support in Congress won’t do much good if Trump himself isn’t promoting effective policies. In particular, it makes little sense for Trump to rail against illegal immigration but then fail to enlist in his fight one of most powerful weapons in the government’s arsenal for deterring illegal immigration, the federal database known as E-Verify.

Many employers use this online network to confirm employees’ work status, but its use isn’t mandatory except for in a handful of states. Trump should demand Congress take action to require all employers use E-Verify in all 50 states — no exceptions.

Trump mentioned E-Verify during his campaign but has been mostly silent on the issue since becoming president, obsessing instead about building a southern border wall. A wall, however, wouldn’t eliminate one of the driving forces of illegal immigration: employment opportunities. E-Verify would help do that by flagging employment applicants who try to get jobs with fake identities and documents.

A 2017 Federal Reserve Bank of Dallas study examined states that require all employers to use E-Verify. It found those states had fewer illegal immigrants living and working there after E-Verify requirements took effect.

After Arizona passed an E-Verify mandate in 2008, the number of illegal immigrants working and living in Arizona fell 33 percent and 28 percent below projections, respectively.

In Alabama, the number of illegal immigrants working there fell 57 percent below projections, while the number living there fell 10 percent.

Mississippi experienced the most dramatic declines: The number of illegal immigrants working and living there dropped 83 percent and 70 percent below projections, respectively.

Of course, these illegal immigrants didn’t necessarily leave the country. They could have easily moved to a state without an E-Verify requirement. That’s why a federal E-Verify mandate is necessary, so workers can’t escape to Wisconsin and other states with loose employment standards. Implementing a federal E-Verify mandate would be relatively easy — a word Trump likes — because the online infrastructure already exists, and maintaining it is much cheaper than building a border wall. …

To be sure, E-Verify alone won’t stop illegal immigration, and an E-Verify mandate should be coupled with reforms to allow industries that rely on illegal labor to hire more legal workers.

— Janesville, Wisc., Press Gazette