San Diego Union Tribune
Section 212(f) of the INA is arguably the broadest and best known of these authorities. It provides, in relevant part, that "Whenever the President finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States [emphasis added], he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or non-immigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate."
Over the years, Presidents have relied upon Section 212(f) to suspend or otherwise restrict the entry of individual aliens and classes of aliens, often (although not always) in conjunction with the imposition of financial sanctions upon these aliens.
Neither the text of Section 212(f) nor the case law to date suggests any firm legal limits upon the President's exercise of his authority to exclude aliens under this provision. The central statutory constraint imposed on Section 212(f)'s exclusionary power is that the President must have found that the entry of any alien or class of aliens would be "detrimental to the interests of the United States."
Beyond Section 212(f), other provisions of the INA can also be seen to authorize the Executive to restrict aliens' entry to the United States. Most notably, Section 214(a)(1) prescribes that the "admission of any alien to the United States as a nonimmigrant shall be for such time and under such conditions as [the Executive] may by regulations prescribe." ... Section 215(a)(1) similarly provides that "it shall be unlawful for any alien" to enter or depart the United States "except under such reasonable rules, regulations, and orders, and subject to such limitations and exceptions as the President may prescribe." In the past, the Executive has relied upon Section 215(a)(1), in particular, to exclude certain aliens. For example, President Carter cited to Section 215(a) when authorizing the revocation of immigrant and non-immigrant visas issued to Iranians during the Iran Hostage Crisis.
These authorities have never been successfully challenged in the past, and it is unlikely that the appellate courts will sustain the lower court actions to prevent the president from exercising this power. From as early as the 1890s, the Supreme Court of the United States declared that immigration policy was solely the province of Congress and the President, recognizing the "plenary power" of the President to execute the laws enacted by Congress without judicial intervention.