Manchin's comments came during an interview with MSNBC, during which he introduced a TV ad responding to an NRA criticizing him for promoting what Manchin called "common sense" gun control laws.
In his commercial, Manchin said he supports the Second Amendment but he believes background checks should be required for firearm purchases.
"I'm a lifetime NRA member, but I don't walk in lockstep with the NRA's Washington leadership, this administration or any special interest group," he says, wielding a gun throughout his commercial. "West Virginia, you know me. I haven't changed and you know I've always fought for our gun rights. I believe that we can protect the Second Amendment and make the community safer. I think most law abiding gun owners agree."
He accused the NRA of using scare tactics to prevent congressional action on gun control.
"Why do we ask to be policy makers and be involved in the public process, when...we're afraid basically to engage," Manchin said on MSNBC "I'm not afraid to engage. The worst they can do is defeat me and send me home to my family and the state I love, West Virginia. That's a pretty good consolation. What are we afraid of?"
The NRA suggested later Thursday that Manchin has two different sides.
"He may speak like an NRA member and tout NRA values when he's in West Virginia but when he's in Washington D.C., he votes the way (New York Mayor) Mike Bloomberg tells him to and repeats all of Bloomberg's talking points," NRA spokesman Andrew Arulanandam told CNN.
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