Here s what we know about the Orlando shooter: the FBI was watching him very closely because of alleged terrorist sympathies. Even though he was on the government s radar, he was able to purchase his weapons legally just days before he killed 50 people and wounded 53 others.Some Americans are just now learning, for the first time, that individuals on watchlists (or who are being monitored by the FBI) can legally buy a gun, no problem, and they cannot be stopped. This is also known as the  Terror Gap,  and like the Charleston Loophole (which allowed Dylann Roof his gun used to kill nine black churchgoers), it exposes fatal cracks in our system.But just 10 days before the Orlando shooting, President Obama warned the people that this fatal crack was detrimental to our national security, and no one paid attention.When asked by a gun owner at a PBS News Hour discussion why he wants to  control and restrict and limit gun manufacturers, gun owners and responsible use of guns and ammunition to the rest of us, the good guys,  and not the bad guys, President Obama responded with:What I have said is precisely what you suggested, which is, why don t we treat this like every other thing that we use? I just came from a meeting today in the Situation Room in which I got people who we know have been on ISIL Web sites, living here in the United States, U.S. citizens, and we re allowed to put them on the no-fly list when it comes to airlines, but because of the National Rifle Association, I cannot prohibit those people from buying a gun.This is somebody who is a known ISIL sympathizer. And if he wants to walk in to a gun store or a gun show right now and buy as much   as many weapons and ammo as he can, nothing s prohibiting him from doing that, even though the FBI knows who that person is.And 10 days later, an ISIL sympathizer walked into a nightclub with his legally bought guns and unleashed the worst shooting in American history.In December, a simple bill in the Senate was shot down by Republican lawmakers. It s purpose? Anyone who appears on watchlists or is being flagged by the government as a terrorist sympathizer may not purchase gun. Every Republican (and one Democrat) voted no. Republicans are so beholden to the NRA that they couldn t even ban potential terrorists from having access to weapons.So the next time Republicans want to blame President Obama, remind them that  he tried to warn us, and that our Republican Senate has blood on their hands.Featured image via Alex Wong/Getty Images