President Donald Trump faces a lawsuit over the federal government declining to issue $1,200 stimulus checks to U.S. citizens who are married to immigrants without Social Security numbers. The litigation comes after the IRS said that only married couples in which both spouses hold valid Social Security numbers will receive the payments.

The suit, filed by a U.S. citizen and Illinois resident identified only as "John Doe," alleges that the ban violates the Constitution and is a form of discrimination "based solely on whom he chose to marry." Two of the attorneys who are representing John Doe told CBS MoneyWatch that more American citizens in the same situation have reached out to them since they filed the complaint.

The stimulus checks are part of the government's $2.2 trillion coronavirus relief package, which provides $1,200 for single taxpayers earning less than $75,000 and $2,400 for married couples earning less than $150,000.

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The plaintiff in the suit would have qualified for a $1,200 stimulus check except that he files taxes with his immigrant spouse, who uses an Individual Taxpayer Identification Number, according to the lawsuit, which also names Senate Majority Leader Mitch McConnell and Treasury Secretary Steven Mnuchin as defendants.

The suit also states that his children are excluded because one parent is an immigrant. Under the Coronavirus Aid, Relief and Economic Security Act, families with children under the age of 17 are entitled to stimulus funds of $500 per child.

"Cruel" exclusion

"It's our humble opinion that U.S. citizens are U.S. citizens," said Lana B. Nassar, an attorney at Blaise & Nitschke, PC, who is representing John Doe. He and others in his situation "aren't asking for preferential treatment — they want to be treated like U.S. citizens."

The "cruel" carve-out violates the Constitution because it discriminates on the basis of marriage, Nassar added. "Time and time again the court has found there is a fundamental right to marriage," she added. "If you are discriminating on the basis of marriage, the government has to show there is a compelling government interest that justifies this exclusion. It's a very high burden to meet."

Nassar added that her client has two children who are citizens under 17. That means the rule is excluding him from a $1,200 stimulus check for himself as well as $1,000 for his children, or $2,200 in total.

"That's money he could use to feed his kids and pay his bills," said Vivian Khalaf, an immigration attorney who is also representing John Doe in the case. "The person suffering here is the U.S. citizen — not the person who doesn't have the Social Security number."

Policy experts have raised concerns that the Corona Aid, Relief, and Economic Security, or CARES, Act bars immigrants, except those with Green Cards that allow them to live and work in the U.S., from receiving the stimulus checks. Many legal immigrants pay taxes and otherwise contribute to the U.S. economy.

Mr. Trump and the other defendants have failed "to treat him as equal to his fellow United States citizens based solely on whom he chose to marry," the lawsuit alleges. John Doe "has lawfully filed taxes in the United States, yet he is being denied the rights and privileges under the CARES Act."

The decision to exclude U.S. citizens who are married to immigrants without Social Security numbers affects 1.2 million Americans, according to the Migration Policy Institute. There were 2.3 million foreign nationals on temporary visas in 2016, according to the non-partisan think tank.

"Presumptively unconstitutional"?

There are two exceptions to the issue that sparked the lawsuit. First, if either spouse is a member of the Armed Forces at any time during the tax year, only one of them is required to have a valid Social Security number, the IRS says.

Second, taxpayers who are citizens and file separately from their immigrant spouses who lack a Social Security number will receive half of the payment for married couples, or $1,200, according to the IRS.

That second exception could give some couples a chance to file their taxes separately, given that the 2019 filing deadline has been pushed back to July 15. However, many taxpayers have already filed their returns for 2019.

Even so, the carve-out that excludes U.S. citizens with immigrant spouses who lack Social Security numbers is harmful and "without serving any legitimate governmental interest," the lawsuit claims.

"Discrimination based on the alienage of a U.S. citizen's spouse is presumptively unconstitutional and subject to strict scrutiny," it claims. The lawsuit was filed Friday in a federal court in Chicago.