Obama Letter to Congress Does Not Satisfy War Powers Act, Much Less Constitution

The War Powers Act states, inter alia:
. . . the President pro tempore of the Senate a report, in writing, setting forth—
(A) the circumstances necessitating the introduction of United States Armed Forces;
(B) the constitutional and legislative authority under which such introduction took place; and
(C) the estimated scope and duration of the hostilities or involvement.

This letter (PDF) doesn't do that. Start with (c). What is the estimated scope and duration?

The War Powers Act also forbids presidential war making except in defense of the United States. As Obama remarked as a candidate:
“The President does not have 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.”

In fact, that's under the War Powers Act. Under the Constitution, the president has no power to launch a war whatsoever.