Donald Trump’s suggestion that armed clubgoers could have prevented the worst mass shooting in modern US history “defies common sense,” according to the National Rifle Association — which is backing the tycoon for president but on Sunday had two of its top officials taking rare exception with him.

“No one thinks that people should go into a nightclub drinking and carrying firearms,” Chris Cox, executive director of the NRA’s Institute for Legislative Action, told ABC’s “This Week.” “That defies common sense. It also defies the law.”

Trump had fired up a Texas rally Friday by saying that if people at the Pulse nightclub in Orlando “had guns strapped . . . right to their waist or right to their ankle,” it would have been a “beautiful sight” to see them shoot “the son of a bitch.”

Cox’s remarks Sunday echoed those of President Obama, who said last Thursday in Orlando that the notion that armed clubgoers could have averted the tragedy “defies common sense.”

NRA CEO Wayne LaPierre said Sunday that pistol-packing revelers is not a good idea.

“I don’t think you should have firearms where people are drinking,” LaPierre told CBS’s “Face the Nation.” He later tweeted, “I want to clarify my comment: if you’re going to carry, don’t drink. OK to carry in restaurants that serve alcohol.”

The NRA endorsed Trump in May, and the mogul has run on a platform of protecting gun owners and the Second Amendment and arming law-abiding citizens to stop bad guys.

After Omar Mateen slaughtered 49 people at Pulse, Trump announced that he wanted to meet with the NRA. He urged the powerful gun lobby to agree to banning people on terrorism watch lists from buying guns.

“We have to make sure that people that are terrorists or have even an inclination toward terrorism cannot buy weapons, guns,” he told “This Week.”

But LaPierre said such a ban would have had no effect in Orlando, since Mateen’s name had been removed from the list.

“NRA didn’t take the guy’s name off the list. The federal government did, FBI did, largely because of . . . some politically correct policies that I think I have been talking about earlier,” he told “Face the Nation.”

Cox, who said the group has “conversations” with Trump often and confirmed a planned meeting, danced around whether the NRA and the mogul saw eye to eye on a watch-list ban, saying the FBI should investigate anyone on its radar who tries to buy a gun.

“If there’s a reason to believe in probable cause that they’re engaged in terrorist activity, they ought to not only be prevented from getting a firearm, they ought to be arrested,” Cox said.

“We want to make sure the terrorists don’t have access to firearms. We also want to make sure that law-abiding Americans have the common-sense ability to protect themselves when the government is failing.”

The Senate will vote on a series of gun-control measures Monday.

The NRA has given its blessing to a proposal by Sen. John Cornyn (R-Texas) that would allow authorities to block gun sales to a person on the terror watch list if they can show probable cause within three days. The Justice Department backs legislation by Sen. Dianne Feinstein (D-Calif.) calling for an outright ban on sales to suspected terrorists.