On Jan. 12, 1991, with 370,000 U.S. troops already deployed near Iraqi-occupied Kuwait, and a U.N. deadline for Saddam Hussein to withdraw from that country only three days away, the U.S. Congress voted on whether to authorize President George H.W. Bush to use force to reverse Iraq's annexation of its neighbor.
The Senate voted 52 to 47 for war -- with Republican Sen. Chuck Grassley of Iowa among those voting no and Democratic Sen. Al Gore of Tennessee among those voting yes.
The House voted 250 to 183 for war -- with three Republicans voting no and 86 Democrats voting yes.
The senior Bush then launched a congressionally authorized -- and, thus, constitutional -- war.
Eleven years later, President George W. Bush sought congressional approval for a second war against Iraq.
On Oct. 10, 2002, the House voted 296 to 133 to authorize it. Six Republicans voted no; 81 Democrats voted yes. The next day, on a 77-to-23 vote, the Senate also authorized war. Democratic senators Hillary Clinton, John Kerry, Harry Reid and Joe Biden all voted yes.
Nine years later, on Dec. 14, 2011, President Obama announced he had successfully completed that war and all U.S. troops were leaving Iraq.
"Indeed, everything that American troops have done in Iraq -- all the fighting and all the dying, the bleeding and the building, and the training and the partnering -- all of it has led to this moment of success," said Obama. "Now, Iraq is not a perfect place. It has many challenges ahead. But we're leaving behind a sovereign, stable and self-reliant Iraq, with a representative government that was elected by its people."
"This is an extraordinary achievement, nearly nine years in the making," Obama said of the way he ended that war.
Two and a half years later, Iraq is in the midst of a sectarian civil war that pits a Shiite-dominated government against a Sunni terrorist group that sprang from al-Qaida.
On Monday, Obama notified Congress "that up to approximately 275 U.S. military personnel are deploying to Iraq to provide support and security for U.S. personnel and the U.S. Embassy in Baghdad."
The Defense Department has moved an aircraft carrier, a guided-missile cruiser, a guided-missile destroyer and an amphibious transport dock ship into the Persian Gulf.
These ships, says Rear Adm. John Kirby, the DOD spokesman, give "the commander in chief additional options to protect American citizens and interests in Iraq, should he choose to use them."
But does Obama have the constitutional authority to use them? Yes and no.