Gerald Posner, author of “Case Closed,” the widely acclaimed book on the assassination of President Kennedy, has penned another blockbuster, “Why America Slept- The Failure to Prevent 9/11.” In it Posner details how over two decades the breakdown in authority, jurisdiction, and communication among the various levels of the government responsible for protecting our borders and preventing terrorist infiltration led directly to the establishment of foreign terrorist sleeper cells in the United States, which culminated in the terrorist bombings of September 11, 2001.

What Posner reveals is nothing short of startling, as he details the misguided complicity of none other than our own Congressman Barney Frank, whose meddling in the immigration laws since the early 1980’s had disastrous consequences:

“Congressman Barney Frank, the Massachusetts Democrat who was a strong advocate of protecting civil liberties, led a successful effort to amend the Immigration and Nationality Act so that membership in a terrorist group was no longer sufficient to deny a visa.”

“Under Frank’s amendment, which seems unthinkable post 9/11, a visa could only be denied if the government could prove that the applicant had committed an act of terrorism. Rendered toothless by the Frank amendment, the Reagan Administration had virtually no way to block entry visas even when there was information linking the individuals to terrorist groups.”

And so it began.

Since 1798 when President John Adams signed into law the Alien Enemies Act, the country had legally and effectively prevented known or suspected enemy agents or terrorists from gaining entry into the United States. But the various amendments to the immigration laws put forth by Barney Frank over the span of two decades derailed this crucial government policy which had worked remarkably well for nearly two centuries.

Between 1981 and 2001, Barney Frank sponsored no less than thirteen amendments to the Immigration and Nationality Act, which had the effect of opening the nation’s floodgates to a well disciplined, well organized network of terrorist sleeper cells and support groups that have since become entrenched here in America for up to two decades.

The Frank Amendment of 1989, the crown jewel of the congressman’s assault on our immigration laws, declared that a foreigner could not be denied a visa because of his ideology, which meant that that no matter how repugnant, hostile, or undemocratic an individual’s politics, these could not be grounds for denying him entry into the United States.

What’s more, the very essence of what constituted terrorist activities was redefined by Frank, as talk show host Chuck Morse explains, “The Frank Amendment raised the bar and made it more difficult for government officials to prove a connection between the visa applicant and terrorist activities. Mere association with a group deemed to be involved with terrorism would no longer be enough to deny a visa as it had been previously.”

Morse continues, “None of those affiliated with Hamas or the 9/11 highjackers who entered the country legally after the Frank Amendment went into effect were formally affiliated with ‘terrorist activities’ by the new and more narrow definition of the term.” Yet the Frank Amendment of 1989 was hardly alone in damaging the national interest. As early as 1981 Frank sponsored an amendment to greatly expand the teacher and student visa program. The new definition for each was so vague and diluted, and the means for verifying that these special visa recipients were actually enrolled as students or teachers was so unenforceable, that the 9/11 terrorist commander Mohammed Atta obtained a student visa knowing that immigration authorities would never check up on him. And he was correct.

In 1995 after Brandeis student Alisa Flatow was murdered by Islamic Jihad in the Gaza Strip, it was revealed that Sami al-Arian, the alleged leader of Islamic Jihad, had easily obtained a teaching visa to the University of Florida, made possible by H.R. Amendment 5287, sponsored by Congressman Frank.

The Frank Amendment opened the doors to our nation for some of the most unseemly characters ever to come out of the Middle East. Aside from the unprecedented influx of foreign terrorists, a large support group of foreign anti-American radical Muslim sympathizers sprouted up in the 1990’s as a result of these new lax visa requirements. This was even further exacerbated by follow up legislation from Mr. Frank, which effectively tied the hands of overseas American consular officials by stripping them of their traditional discretion in granting visas, then impeding the CIA and FBI from even sharing information about these questionable aliens once they landed in America. Sheik Omar Abdel Abdul Rahman, leader of the original World Trade Center bombing, also benefited from the Frank Amendment. He and his terrorist cell received visas because there was no indisputable proof that they had committed past terrorist acts. So under the Frank Amendment, they couldn’t legally be denied visas. Hence, American counselor officials in the Middle East, along with the FBI and CIA, could do little to stop the Sheik Rahman’s of the world from entering the country, courtesy of Mr. Frank. So having sabotaged those immigration laws which had succeeded in keeping out foreign terrorists for nearly two centuries, Frank then proceeded to launch a campaign against CIA funding during the Democratic Clinton Administration, which resulted in severe CIA budget cuts in 1996, despite dire warnings from Clinton’s CIA Director George Tenet of an ominous terrorist threat.

In my conversation the other day with Mr. Frank, he referred to Posner’s book (soon to be made into a TV miniseries) as “a shockingly bad book.” He then railed against his political nemesis Chuck Morse as “delusional,” and predictably blamed the Republicans whom, he contends, “rewrote the immigration laws in 1995.”

In the last congressional campaign Mr. Frank found himself in the unusual position of being put on the defensive, and even uttered a falsehood that the 9/11 highjackers were here illegally. Yet of the nineteen highjackers, all but three were here legally, and he knew it.

Because it was Barney Frank, after all, who made it possible for the 9/11 terrorists to legally enter -and remain in- the United States… which likely explains why he was recently dropped from the Congressional Committee on Homeland Security.

Tom Mountain is a staff columnist for the Newton TAB, in Newton, Mass.