ABC’s Z. Byron Wolf reports: The Times Square bombing failed, but terrorists are already plotting their next move, according to New York Mayor Michael Bloomberg and Police Commissioner Raymond Kelly, who lobbied Congress today ban people listed on the terror watch list from buying guns. People on the watch list can buy weapons under current law – the New York officials called it the “terror loophole.” “We are the target. We are going to be the target again,” Bloomberg told a Senate panel, adding, “the next attack will be different.” Terrorist bombers could cause massive casualties if they successfully detonated explosives within the United States. But the Times Square bomber, the Christmas Day bomber, the men who plotted to release cyanide in the New York City Subway all could have something in common – failure. In fact, the only successful terror attacks perpetrated within the United States since 9/11 were with guns. That’s a point Sen. Joe Lieberman, I-CT, made in pushing for the legislation. The only terror attacks since 9/11 “that have taken American lives were carried out with firearms,” said Lieberman. “The threat is real,” he said. “Terrorists with high powered automatic could inflict heavy casualties in seconds.” Rep. Peter King, R-NY, a hawk on terrorism issues, told the Senators that if Congress has the ability to exclude people on the watch list from buying a gun, they should do it in the off chance that someone on the list went on a rampage. “There would be blood on our hands. We would be responsible for the deaths of all those people,” he said. Kelly told Senators that New York police officers train against the threat of a coordinated attack by armed gunmen like the one that shut down Mumbai, India in 2008 and led to 166 deaths. Currently, people who are on the government’s terrorist watch list, even though they cannot board an air plane, can purchase handguns. A recent Government Accountability Office report showed more than a thousand instances of people listed on the terror watchlist buying weapons. 90 percent of those completed the purchase, although none of the weapons were yet used in any crime. “If society decides that these people are too dangerous to get on an airplane with other people then it’s probably time to look very hard if they should have a gun,” said Bloomberg. But there is nothing in the Constitution about airports, magnetometers or no-fly lists, said Sen. Lindsay Graham, R-SC. There is, he pointed out, clear language about the right to bear arms. “There is no constitutional right to get on an airplane without being screened. That I know of,” said Graham. He equated banning gun purchases for people on the terror watch list with attempts by other lawmakers to ban handguns period. “I don’t think banning handguns is going to make me safer,” said Graham. There was spirited debate between Lieberman and Graham, normally allies on national security issues. Lieberman said 2nd amendment rights, just like the 1st amendment right to free speech, cannot be unlimited. Graham did say that a person’s rights as a citizen should be abridged if they are suspected of being a terrorist. He said authorities should be able to consult a secret FISA judge to keep a suspected terrorist like Faisal Shahzad out of the legal system and without their Miranda rights. “I don’t think it’s smart to us to say the homeland is not part of the battlefield,” said Graham.