Florida Congressman Alan Grayson announced plans to file suit challenging Texas Republican Senator Ted Cruz's legal eligibility to assume the Oval Office as president.

U.S. News reports 2016 Republican front-runner Donald Trump first raised the issue this week, suggesting party faithfuls should tread carefully in displaying support for Cruz. Trump suggested his rival's supporters run the risk the Republican candidate would be "hogtied" by Democratic legal challenges over his Canadian birthplace, should Cruz ascend to the White House.

Now comes word Grayson, also an attorney and Democratic Senate candidate, is already in the process of drafting language for the suit, should Cruz overtake Trump and win the party's nomination.

The 45-year-old Texas senator was born in Calgary, Canada to an American mother and a Cuban father who later gained U.S. citizenship. Currently, no court precedent exists to determine if foreign-born Americans meet the Constitution's "natural-born citizen" requirement for the presidency.

"If he's not qualified to be president according to our Constitution, then he certainly should not serve," Grayson said. "There's quite a lot of stuff here."

Grayson added Cruz's mother, Eleanor Darragh Wilson, may have forfeited her right to U.S. citizenship by taking a Canadian oath of citizenship. In addition, he pointed out there's no concrete evidence she was actually born in the U.S.

Campaigning in Iowa on Wednesday, Cruz told reporters of the issue, "As a legal matter it's quite straightforward," and called it "settled law."

Grayson sharply drew distinctions between the questions he has raised about Cruz's eligibility and the so-called birthers who have dogged President Obama throughout his two terms with questions about his eligibility and the issue of where he was born.

"The Obama birthers are loons," he said. "There's no plausible legal argument that Obama is not qualified to be president, that's ridiculous. There's a very good legal argument that Ted Cruz is not qualified to be president."

In the past, Cruz spokesperson Rick Tyler has pointed to a Harvard Law review article as ironclad proof of the candidate's standing. The article, from a pair of former solicitors general, proclaims Cruz a natural-born citizen and thus legally eligible to be president.

Recent polls now show Cruz leading Trump in the critical, early-voting state of Iowa.