Now Donald Trump is questioning Marco Rubio' eligibility for the presidency.

In a tweet Saturday, Trump shared a video of what appears to be an attorney making a bizarre case that not only Texas Sen. Ted Cruz, who was born in Canada, but Rubio, whose parents immigranted from Cuba, is not eligible to become president.

In the tweet to his 6.3 million followers, Trump quoted a message sent to him by another Twitter user, who at the time appeared to have five followers: "@realDonaldTrump Mr. Trump...BOTH Cruz AND Rubio are ineligible to be POTUS! It's a SLAM DUNK CASE!! Check it!"

The tweet links to a video on the website of the Powdered Whig Society, a group that says it is dedicated "to the restoration and strict obedience to the United States Constitution."

Trump has aggresively questioned Cruz's eligibilty to become president and has threatened to sue to challenge Cruz's eligibility to run for thle office. Until Saturday, Trump avoided questioning Rubio's eligibility.

The 12-minute video shows an unidentified woman who is purported to be a litigation attorney describe what it means to be a natural born citizen. She argues that both Rubio and Cruz are citizens, but not "natural born citizens" according to the Constitution, which says only natural born citizens may become president.

Rubio was born in Miami. That makes him a natural born U.S. citizen under the Constitution. But the unnamed woman in the video Trump posted says he is not a "naturalized citizen," because his citizenship is defined under Section 1 of the 14th Amendment. If not for this "man-made law," she says Rubio would have been born a "resident alien," the same status of his parents, both of whom were Cuban nationals.

The supposed attorney later goes on to call Congress using laws to change the original text of the Constitution as "ridiculous."

"In order to understand the genuine meaning of a text, we must use the definition the framer's use, otherwise texts become like Play-Doh. They mean whatever you want them to mean to get the outcome you want," she says.

Cruz, who was born in Canada to father who was a Cuban national and an American mother. Some legal scholars says that leaves his eligibility to run for president in question. But the supposed attorney makes a far more questionable case. She argues that when the Constitution was written, a woman's legal identity was subsumed into her husband's. That would also disqualify Cruz, she says, because it is necessary that he be born of a father who is a citizen.

When the Constitution was written in the 1780s, the purported attorney says all the framers knew what a natural born citizen was, using a definition provided in Swiss philosopher and legal expert Emerich de Vattel's book on political philosophy The Law of Nations. In it, she says, a child's status as a citizen is defined as being inherited from the father, and that it does not matter where the child is born.

Like his eye color, citizenship is "inherited by his parents, it's in his blood," she says. "Not an act of Congress."

Watch the video below: