Mr. Obama’s notification letter does not satisfy the constitutional requirement that Congress approve military action, says Lou Fisher, former researcher with the Congressional Research Service and an expert on war powers. Mr. Fisher also raised objections to Mr. Obama citing United Nations authorization in his letter.

“It’s impossible for Congress to take its war powers and give it to the U.N.,” Mr. Fisher said. “Other than defensive actions—and there’s no defensive actions here—this has to be done by Congress.” [bold mine-DL]

The president, with his letter, appeared to meet the requirements of the 1973 War Powers Resolution, which says only that in cases where the president doesn’t seek prior approval from lawmakers, the president must notify Congress within 48 hours of committing armed forces to military action and puts a 60 day deadline on such actions. ~The Wall Street Journal

Weigel has the text of Obama’s letter to Congress here.