Strawman.  He didn't say it was his biggest concern.  He said he was "a bit concerned."

That aside, I agree with Lee.  Amazing, but true.  We conservatives believe in the rule of law, and above all, the Constitution.  The executive's powers during times of war are great, for which reason his powers are dependent on the (exclusive) power of Congress to DECLARE war.  That is as it should be.  War is too great a course to be left to the decision of one person.  We are about to bomb the crap out of North Korea, an act of war.  The nation should be on board, or we don't do it.  (In which case we live under the unending threat of a hostile nation that's announced its intention to use the bomb on us.)