Dude Abides said:No.
He's invoking his constitutional AND statutory authority. This is essentially the argument, made sub silentio here, that the WPR is unconstitutional if it infringes on his CiC constitutional authority. As a conservative, you should love this.
Please link me to that part of the Constitution, because in 2007 he said this: "The President does not have any power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation.