Wyoming Congresswoman Liz Cheney says she is ''not optimistic" about the chances of a diplomatic solution to the North Korean nuclear threat to the United States and its allies.

The first-term Republican says she wants to continue diplomatic efforts to get North Korea to give up on nuclear missiles capable of threatening the United States. But she goes on to say ''I am not optimistic that we are ever going to be able to talk him (North Korean leader Kim Jong-un) out of his nuclear weapons program."

She said at this point ''we can only assume'' that Korean nuclear missiles are capable of striking the U.S. mainland. Rep. Cheney also said that means the United States needs to take steps to beef up its missile defenses, adding the defense department will be asking for some supplemental funding from Congress to do that.

The congresswoman also says that the likely solution to North Korean nuclear threat will be to get China more actively involved in resolving the situation.

Rep. Cheney says that will probably only happen if China believes the U.S. "Will take military action if we have to." She says it's important that the Chinese ''make sure he doesn't stay in power very much longer."