BROWNSVILLE, TEXAS (TIP): Federal immigration officials will be breaking the law if they carry out President Barack Obama‘s executive order to let at least 4 million undocumented immigrants stay in the country, attorneys for Texas argued as they urged a U.S. judge to block the policy now while he decides whether it’s legal.

Texas, joined by half the states, asked U.S. District Judge Andrew Hanen at a hearing Thursday, January 15 in Brownsville to block Obama’s immigration policy until they’ve had a chance to fully challenge it in court. Hanen didn’t issue a ruling.

“The president does not get to decide what the law is,” Andrew Oldham, an attorney for Texas, told Hanen at the hearing.

Obama’s Nov. 20 order grants quasi-legal status to more than a third of the estimated 11 million undocumented immigrants already in the U.S. Undocumented immigrants must have been in the country for more than five years or have a child who is a U.S. citizen, or have been brought here themselves as children, to qualify for U.S. work permits and be protected from deportation under the new policy. They must also pass a criminal background check.

Thursday’s hearing follows the Jan. 14 vote in the Republican-led U.S. House of Representatives to slash funding for the immigration programs at the heart of Obama’s policy.

At issue in court is whether the president can “unilaterally suspend federal immigration laws,” create a “massive” bureaucracy and hand out millions of dollars in benefits, and then insulate that decision from review “by any court at any time by calling it executive action,” Oldham said. “States representing half of this country say he cannot.”

A dozen more U.S. states, in court papers filed last week, urged Hanen, whose courthouse is less than a mile from the Mexican border, to reject attacks on the president’s immigration order. States backing Obama say the policy will benefit the economy, law enforcement and immigrant families.

Texas filed its case at the state’s southernmost tip, where issues concerning illegal immigration have dominated headlines for more than a year. Brownsville has a front-row seat to the “humanitarian crisis” that has swept more than 1,000 undocumented immigrants a day – many of them unaccompanied children – across its border in the past year, according to the states’ complaint.

“We’re where the rubber meets the road,” Hanen told lawyers Thursday. “Within a few miles of this courthouse, there are probably thousands of illegal aliens doing nothing more than trying to make a better life for their families.”

Unless Hanen blocks them, immigration officials will soon begin processing paperwork to protect certain immigrants from deportation and provide them with temporary work permits and some federal benefits including Social Security and Medicare, a process the states say will be tough to stop once it starts.

“Granting an injunction would preserve the status quo,” Oldham said. “And give 25 states a day in court” before the policy takes effect, he added.

Texas, which sued the Obama administration on Dec. 3, seeks to overturn the president’s policy, which was made without approval of Congress. The states say Obama violated the Constitution and lacks authority to grant federal benefits to people who enter the country illegally.

U.S. lawyers on Thursday urged Hanen to deny the states’ bid, arguing that the federal government has broad discretion under the Constitution to “prioritize enforcement resources.”

“The purpose of this policy is to continue to focus on our priorities, which are to stop border crossings and remove threats to our nation,” Kathleen Hartnett, a Justice Department lawyer, told Hanen.