Asking the Republican-controlled House of Representatives and the Democratic-led Senate to agree on military action – already a controversial issue both within and between the parties – injects a new dose of uncertainty into Washington’s reaction to the Syria crisis.

Because Congress will not even begin floor debate until September 9 at the earliest, a question mark will hang over Washington’s Syria policy for weeks, punctuated by emotional and probably bitter debate.

That became evident on Saturday immediately after President Barack Obama’s surprise announcement that he would seek authorization for limited military strikes in Syria from members of Congress, many of whom, he has complained, reflexively oppose anything he proposes.

No one knowledgeable about Congress was willing to predict with any confidence how it would deal with a resolution to permit strikes in Syria.