House Judiciary Committee Chairman Jim Jordan (R-OH), Rep. Chip Roy (R-TX), and 16 other lawmakers filed an amicus brief in one of the birthright citizenship lawsuits, asking a judge to deny an emergency request made by four blue states to block the controversial order from taking effect.

The Republican lawmakers argued that the order, which Trump issued on his first day in office, correctly interpreted the citizenship clause of the Constitution, which states that “all persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States.”

Trump’s order would reverse the government’s 150-year-old practice of granting automatic citizenship to children born to mothers living in the United States illegally or to noncitizen mothers who temporarily visit the United States. Republicans say the process has been abused.

While the order came as expected after Trump promised to fight the Constitution’s citizenship clause as part of his campaign, it was immediately met with five lawsuits across the country and is set to eventually land in front of the Supreme Court.

At issue is the 14th Amendment’s language about children born in the United States who are “subject to the jurisdiction” of the country. Courts have uniformly interpreted the phrase to exclude only children born to people whose allegiance is to another country, such as foreign ambassadors or invading soldiers. The House Republicans believe that interpretation is incorrect.

“There is a wealth of support for the proposition that the [Jurisdiction] Clause applies the same to children of those illegally present in the country because they (like ambassadors and foreign soldiers) do not owe total allegiance to the United States,” attorneys for the Republicans wrote.

The attorneys said people living in the country illegally or temporarily visiting “owe at least divided allegiance” to their home countries.

The House Republicans, who filed their brief in the Western District of Washington, aim to prevent the court from blocking Trump’s order, which would otherwise go into effect at the end of this month.

The only obstacle to the order, at present, is a two-week restraining order, which Judge John Coughenour, a Reagan appointee based in the Washington district, issued on Jan. 23 after hearing oral arguments on the matter.

“I’ve been on the bench for four decades. I can’t remember another case where the question presented is as clear as this one is,” Coughenour said.

Nearly two dozen states, along with the American Civil Liberties Union, a handful of pregnant noncitizen women who say they will be affected by the order, and several other activist groups have joined in on the lawsuits. In the Washington case, attorneys for four states argued that the 14th Amendment’s “operation is automatic and its scope broad.”

“It provides our Nation a bright-line and nearly universal rule under which citizenship cannot be conditioned on one’s race, ethnicity, alienage, or the immigration status of one’s parents,” the attorneys wrote.