A former top immigration official says federal law is very clear in giving the president of the United States broad power over who is allowed into the country, and he points out that possession of a visa does not give permission to enter the United States.

The issue is still at a boiling point after federal Judge James Robart placed a temporary restraining order on President Trump's executive order pausing immigration to the United States from seven nations roiled by radical Islamic terrorism.

In his ruling, Robart said he was granting the injunction because the plaintiffs were likely to win in the merits and individuals and the states could suffer irreparable harm before the case is fully resolved.

Jan C. Ting served as assistant director of the Immigration and Naturalization Service at the Justice Department during in the George H.W. Bush administration. He now teaches at the Temple University School of Law. He told WND and Radio America the law is clearly on Trump's side.

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"The law is very clear that Congress has authorized the president to decide. If the president finds the entry of any aliens or any class of aliens would be detrimental to the interests of the United States, he is authorized to suspend the entry of all aliens or any class of aliens or to impose on the entry of aliens any restrictions he may deem to be appropriate," Ting said.

"It's codified as Immigration and Nationality Act, Section 212 (f). It's also codified as 8 USC Section 1182 (f). It gives broad power to the president to exclude, basically, any aliens or non-citizens he chooses on the grounds that it would be detrimental to the interests of the United States," Ting explained.

Listen to the WND/Radio America interview with Jan. C. Ting:

He said this should be an open and shut case for the courts in the Trump administration's favor.

"I think the courts, if they follow the precedents, have to come up with that result, and I hope they will," Ting said.

Robart did not cite any constitutional provision or U.S. statute. The only court cases he cited dealt with his power to issue an injunction. Ting said the ruling was unconvincing.

"I didn't find the temporary restraining order terribly persuasive. I thought the judge relied on generalities about the law and the Constitution and our customs and practices," Ting said.

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Professor Ting is also taking aim at some of the legal arguments against the executive order, starting with the contention that anyone in possession of a U.S. visa has a right to enter the country.

"People need to understand what a visa is. All a visa is is permission to get on an airplane coming to the United States," Ting said.

"If you don't have a visa, you can't get on the airplane, but the visa does not itself authorize anyone to come into the United States. They have to present themselves for inspection and the inspectors are authorized to turn people around, even if they have visas."

And that is why Ting said citing a 1965 law barring discrimination against aliens from a particular country doesn't matter in this case. He said that law also focuses only on visas and not actual entry into the United States. He said Section 202 (a) of the Immigration and Nationality Act makes that clear.

"I think it's clear that the 1965 language in 202 (a) does not apply to the inadmissability language in 212 (f)," Ting said.

Nonetheless, if the courts continue to rule against the Trump administration, Ting said it's up to Congress to clarify statutory language even more to make sure the law is being followed as the original lawmakers intended.