It isn’t all that often that Donald Trump would ever make a mistake. But in this case, there’s little doubt The Donald would happily acknowledge his misstep. Especially considering the slip-up is in regards of tens of thousands of refugees from mainly Muslim nations.

As recently quoted, the New York City multi-billionaire accused Hillary Clinton of planning to “massively increase admissions (of Middle East refugees) … including a 500 percent increase in Syrian refugees coming into our country.” Yet after a little fact checking by C. Eugene Emery Jr. of PolitiFact.com on June 13, 2016, it turns out the Republican presumptive nominee has given Hillary a bit of an underestimation on how many she wants to admit to the good ol’ US of A.

As Emery uncovered, Clinton actually has vowed to increase Middle Eastern immigration by a total of 550 percent. In an appearance on CBS’ Face the Nation last September, when she was asked if Barack Obama’s plan to increase the total number of refugees allowed entry into the United States to 10,000 was enough, vice the 2,000 allowed in 2015, Clinton made clear her very giving policy.

As Obama’s ex-Secretary of State said, “Look, we’re facing the worst refugee crisis since the end of World War II, and I think the United States has to do more, and I would like to see us move from what is a good start with 10,000 to 65,000 and begin immediately to put into place the mechanisms for vetting the people that we would take in.” The Clinton proposed increase would actually be a 550 percent increase.

Now enter the 800-pound gorilla into the room most everyone fails to notice. As noted by the Chicago Tribune’s reporter David Gomez on June 14, 2016, self-professed Islamic jihadist Omar Mateen, the killer who just committed the largest terrorist attack on American soil since 9/11, was under FBI surveillance — not once, but twice — over the past few years for terrorist-related associations.

And as Gomez correctly cited, the perpetrator of the Orlando Massacre isn’t the only one who’s managed to slip under the FBI’s radar. The now dead half of the Boston Bombing brother duo, Tamerlan Tsarnaev, had his chummy dealings with known terrorists in the Islamic jihad hotbed of Dagestan was brought to the attention of the FBI by the Russian State Police. Unfortunately for the almost 300 innocent people killed or wounded by Dzhokhar and Tamerlan Tsarnaev, the FBI file on the two died a whimpering death.

Then comes the case of the San Bernardino terrorist attack of last December which killed or wounded 40 innocent people. As The New York Times reported at the time regarding the husband and wife terror team, “Ms. Malik faced three extensive national security and criminal background screenings. First, Homeland Security officials checked her name against American law enforcement and national security databases. Then, her visa application went to the State Department, which checked her fingerprints against other databases. Finally, after coming to the United States and formally marrying Mr. Farook here, she applied for her green card and received another round of criminal and security checks.”

And as they say on late night infomercials, but wait… there’s more. “Ms. Malik also had two in-person interviews, federal officials said, the first by a consular officer in Pakistan, and the second by an immigration officer in the United States when she applied for her green card. All those reviews came back clear, and the F.B.I. has said it had no incriminating information about Ms. Malik or Mr. Farook in its databases.”

Lastly would be the case of Nidal Hasan, the ex-US Army officer who opened fire at a Fort Hood, Texas administrative center, killing or wounding 46 innocent people (to include one unborn child). Besides the standard background checks the Army conducts on all its soldiers, especially officers, precious little was done in the face of Hasan’s blatantly open alliance with the Islamic jihad movement.

As Fox News noted, Hasan “had called himself a ‘soldier of Allah’ on business cards found in his apartment after the shooting rampage at Fort Hood in which he is accused of murdering 13 people. Hasan, an Army psychiatrist, reportedly obtained the business cards over the Internet. In addition to listing his profession and contact information, the cards contain a discrete reference to his religion: ‘SoA(SWT).’ Watchdogs say the first letters are shorthand among militant Muslims to “soldier of Allah.” The last letters refer to ‘Subhanahu Wa Ta’all,’ which means ‘glory to God.'”

Perhaps much more troubling than a set of rather cryptic initials on a business card, the New York Times reported that even though the FBI knew of Hasan exchanging 10-20 emails with the now dead Anwar al-Awlaki, there was really nothing to see here, everyone just keep moving along. As counterterrorism and military officials said of the rather suspicious email with al-Qaeda’s top recruiter, Hasan’s communications “were consistent with a research project” he was conducting.

Trending: Two Campaign Workers For Ilhan Omar’s GOP Opponent Shot, One Fatally

The six perpetrators of the four bloodiest terrorist attacks since September 11th were all at one point in time under the scrutiny of the federal government, mostly by the FBI. Yet all six passed their vetting with flying colors.

More than a few have asked rhetorically: If the federal government fails to properly vet a mere six individuals who killed or wounded nearly 550 innocent men, women and children, why should we believe the feds when they assure us that they can properly investigate 65,000 refugees from Syria and Iraq? It should also be noted that ISIS has vowed they would embed their followers in with the huge numbers of refugees that are already overwhelming the authorities of many European nations.

Related: