Always.

The first time that Obama nearly ordered a strike on Syria without congressional permission, he was going to target the country's repressive dictator. He "abruptly changed course" at the last moment and sought legislative input. In doing so, he avoided an intervention that the American public did not support. The New York Times nevertheless characterized that act of deference to the Constitution as a "risky gamble" for the White House, as if the country was clamoring for a new war. As predicted, the public forgot about Syria as soon as it faded from the news, and Obama paid no political price for not bombing the country.

Today, the White House is once again signaling that war may be close at hand, though this time instead of striking Syria's dictator, there is talk of U.S. air strikes against ISIS, a radical Islamist group that Syria's dictator is currently fighting. Picking up on the hawkish shrieks of Chuck Hagel and John Kerry, The New York Times notes that "Obama has authorized surveillance flights over Syria, a precursor to potential airstrikes there," while Yahoo News reports that the White House has no plans to ask Congress for permission if it decides to start bombing.

That is scandalous, though many journalists don't seem to agree. "The White House maintains the president has the authority to act unilaterally in Syria and Iraq for now," Lauren Fox declared at U.S. News and World Report. "The War Powers Act gives the president 90 days to intervene militarily without congressional approval."

Incorrect! The War Powers Resolution does no such thing. Read it yourself:

The constitutional powers of the President as Commander-in-Chief to introduce United States Armed Forces into hostilities, or into situations where imminent involvement in hostilities is clearly indicated by the circumstances, are exercised only pursuant to (1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.

The language is unambiguous. Absent a declaration of war or a statutory authorization from Congress, the president can't introduce the U.S. Armed Forces into hostilities save in "a national emergency created by attack upon the United States." If the president lawfully begins hostilities abroad due to such an attack, then he has 60 days to engage in hostilities without congressional approval. A 30-day extension can be obtained, but only if "the President determines and certifies to Congress in writing that unavoidable military necessity respecting the safety of United States Armed Forces requires the continued use of such armed forces in the course of bringing about a prompt removal of such forces." The War Powers Resolution is not a 90-day blank check for war! It's the same statute the Obama administration violated when it attacked Libya.