It is one of the ironies of American political life that the senator most hostile to the proposal to legitimize millions of undocumented Americans is himself an immigrant and Hispanic and Irish.

Senator Rafael (Ted) Cruz of Texas is a Canadian native who moved to America with his father, a Cuban immigrant, and his Irish American mother when he was four years old, in 1974.

Over the weekend he forced the senate to stay in session because of the Obama executive order, incensing his own colleagues in the GOP who wanted to get out of town.

Lame duck Senate Majority Leader Harry Reid used the opportunity and extra time to pass through 24 nominees to the Obama administration that the GOP opposed.

As Politico noted:

“The fiasco has turned many of Cruz’s colleagues openly against him, a dynamic that might bolster his cred with the tea party wing of the party if he makes a run for the GOP’s presidential nomination in 2016, but could also leave him vulnerable to attacks that he’s more troublemaker than leader — able to shut down the government or stall votes but unable to advance a proactive agenda.”

The irony of a Hispanic immigrant forcing a split and deep divisions in his own party on the issue of immigration is certainly worth noting.

But Ted Cruz sees little contradiction in his stance. He sees it as necessary to burnish his credentials for his presidential run despite the fact there is a legitimate question on whether he can even run for president.

He was born in Canada so he cannot run for president right?

Wrong. It appears his Irish American mother can make him eligible.

Cruz was born in Calgary, Alberta, Canada, where his parents, Eleanor Darragh and Rafael Cruz, were working in the oil business. His father fought the right wing Batista regime in Cuba before fleeing.

But what makes him eligible to run for president?

Cruz's mother was born and raised in Delaware, in a family of Irish and Italian descent.

Cruz has said, "I'm Cuban, Irish, and Italian, and yet somehow I ended up Southern Baptist."

Cruz has been visiting early primary states. National Review, the conservative bible, has urged him to run.

“It is an undercurrent and growing,” Texas GOP consultant Bill Miller told the Washington Post.

“Most observers believe he is moving very fast toward a much higher visibility. The presidential buzz has begun in earnest.”

Jeff Judson, a major tea party figure in Texas wants him too.

“Yes, there is a buzz about Cruz running for president, but a different kind of buzz than with other prior candidates,” Judson said.

“He has serious gravitas - more than all the 2012 Republican presidential candidates combined.”

But is he a “natural-born citizen,” as the 14th Amendment says presidents must be?

Cruz’s mother was a U.S. citizen when he was born so he is a U.S. citizen too regardless of where he was born. But does that make him a “natural-born citizen.”

Legal scholars say most likely yes, but it has never been tested.

Democrats in 1967 tried to disqualify George Romney, Mitt’s father because he was born in Mexico. But a New York Law Journal piece at the time made a very persuasive case otherwise. The debate goes back to President Chester Arthur who many claimed was born in Canada.

The nonpartisan Congressional Research Service has found that candidates like Cruz “most likely” qualify as natural-born citizens.

“The weight of more recent federal cases, as well as the majority of scholarship on the subject, also indicates that the term ‘natural born citizen’ would most likely include, as well as native born citizens, those born abroad to U.S. citizen-parents, at least one of whom had previously resided in the United States, or those born abroad to one U.S. citizen parent who, prior to the birth, had met the requirements of federal law for physical presence in the country,” wrote Jack Maskell.

So Ted Cruz may have his Irish American mother to thank for his eligibility to run for president.

And the establishment GOP has its biggest headache in years it seems.

Senator Ted Cruz as much a headache for GOP as President Obama.Getty Images