The executive branch has broad discretion through this authority. In 2015, the Supreme Court ruled that the government can deny someone a visa on national security grounds without a specific reason.
Interestingly, it was a fear of communists that drove Congress to give this power to the president more than six decades ago. President Harry S. Truman vetoed the Immigration and Nationality Act of 1952 — and in a lengthy statement, he cited concerns about broad powers being granted to the executive branch, even to “minor immigration and consular officials.”
.. Truman wrote in his veto statement: It repudiates our basic religious concepts, our belief in the brotherhood of man, and in the words of St. Paul that “there is neither Jew nor Greek, there is neither bond nor free …. for ye are all one in Christ Jesus.”
But Congress overrode Truman with a bipartisan veto-proof majority.
.. Of about 400 individuals charged with or credibly involved in jihad-inspired activity in the U.S. since 9/11, just under half (197) were U.S.-born citizens, according to research by the nonpartisan think tank New America Foundation. An additional 82 were naturalized citizens, and 44 were permanent residents.
“Far from being foreign infiltrators, the large majority of jihadist terrorists in the United States have been American citizens or legal residents. Moreover, while a range of citizenship statuses are represented, every jihadist who conducted a lethal attack inside the United States since 9/11 was a citizen or legal resident.
.. Trump’s executive order applies to migrants, refugees and U.S. green-card holders from seven countries: Iraq, Iran, Sudan, Somalia, Syria, Libya and Yemen. That means the order would not have prevented some of the most high-profile terrorist attacks by individuals from countries excluded from that list, including the 9/11 hijackers, the San Bernardino attackers and the Boston Marathon bombers.
.. “The threat to the U.S. homeland from refugees has been relatively low. Almost none of the major terrorist plots since 9/11 have involved refugees. Even in those cases where refugees were arrested on terrorism-related charges, years and even decades often transpired between their entry into the United States and their involvement in terrorism. In most instances, a would-be terrorist’s refugee status had little or nothing to do with their radicalization and shift to terrorism.”
Trump’s flashy executive actions could run aground
The White House failed to consult with many of the agencies and lawmakers who will be critical for their success.
President Donald Trump’s team made little effort to consult with federal agency lawyers or lawmakers as they churned out executive actions this week, stoking fears the White House is creating the appearance of real momentum with flawed orders that might be unworkable, unenforceable or even illegal.
The White House didn’t ask State Department experts to review Trump’s memorandum on the Keystone XL pipeline, even though the company that wants to build the pipeline is suing the U.S. for $15 billion, according to two people familiar with the matter.
Defense Secretary James Mattis and CIA Director Mike Pompeo were “blindsided” by a draft order that would require agencies to reconsider using interrogation techniques that are currently banned as torture, according to sources with knowledge of their thinking... Just a small circle of officials at the Department of Health and Human Services knew about the executive action starting to unwind Obamacare, and only less than two hours before it was released. Key members of Congress weren’t consulted either, according to several members... For example, there are legal questions on how the country can force companies building pipelines to use materials manufactured domestically, which might not be available or which could violate trade treaty obligations... Trump, less than a week into his presidency, is continuing the improvisational style he used to run his company, his campaign and his transition. He’s relying on a small circle of trusted advisers to act decisively. And he’s emphasizing the theatrics of autographing official-looking leather-bound documents in the Oval Office... There’s also an irony in Trump flexing his executive power so fully because the approach goes against what Trump and Republican members of Congress have said about executive actions in the past.For example, in 2012, Barack Obama’s increased interest in using executive orders developed a critic: a certain Manhattan billionaire. “Why is Barack Obama constantly issuing orders that are major grabs of authority?” Trump asked on Twitter... Former Senate Majority Leader Trent Lott, now a lobbyist, said he continues to have deep reservations about any aggressive use of executive action, whether it comes from a Republican or Democrat.
“You don’t want to have an imperial president,” Lott said. “It’s just not the best way to govern. These things need to be figured out by Congress. We have allowed the presidency to become too powerful.”
.. Experts warned that the quick moves could hurt Trump down the line and cause him to eventually slow down.