Speaking at the White House on Wednesday, U.S. President Donald Trumpdefended his targeted killing of an Iranian general.Qassem Soleimani was the head of Iran's Quds Force.He died last Friday in a U.S. airstrike near Baghdad International Airport.His death increased tensions in the area.Iran has already answered by firing missiles into Iraq.The missiles landed at two military bases that house U.S. troops.No casualties from that attack were reported.Trump did not speak Wednesday about using additional military force against Iran.Instead, he said he would put more economic restrictions on the country.But many American lawmakers are expressing concernsabout open war between the two countries.They will vote this week on a measure to prevent U.S. military forcesfrom taking action against Iran unless Congress approves.The U.S. Constitution says Congress has the authority to declare war.And it says the president is the commander-in-chief of the military.The men who wrote the Constitution divided these powers on purpose.They wanted to prevent one person or group from making a sudden movetoward war without others in the government agreeing.But lawmakers and the president have often clashed over how to operatewithin the rules of the Constitution.The last time Congress officially declared war was almost 80 years ago, during World War II.American military actions since then have happened without an official declaration of war.In 1973, Congress passed the War Powers Actto further define the president's role in directing military actions.The law required that U.S. presidents had 38 hours to report to Congressafter committing U.S. forces to military actions overseas.The president must also officially say why she or he is committing forces.In 2001, lawmakers and the president worked together to create a resolutionpermitting actions to answer terrorist threats.It is called the Authorization for Use of Military Force, or AUMF.The AUMF is unusual because it permits actions against groups or people, as opposed to nations or areas.The resolution has created debate under Presidents George W. Bush, Barack Obama, and Trump.All three leaders have used the AUMF's large definition of a terrorist threatto say military actions are needed.Observers say Trump appears to be using his ability to strike under the War Powers Act,which permits the president to use military force to answer an attack.Trump's government noted intelligence they say pointed to planned attackson Americans as a reason for the airstrike.In a tweet on Sunday, Trump wrote, "These Media Posts will serve as notificationto the United States Congress that should Iran strike any U.S. person or target,the United States will quickly & fully strike back, & perhaps in a disproportionate manner.Such legal notice is not required, but is given nevertheless!"Lawmakers from the opposition party to the president, the Democrats,have expressed concerns about how Trump's government told lawmakers about the airstrike.Some want to require Trump to discuss increasing hostilities against Iran with Congressand the public before taking action.For his part, Trump on Wednesday called on the security alliance of NATOto become "much more involved in the Middle East process."