President Obama announced Thursday night that the United States would "take targeted strikes against ISIL [Islamic State] terrorist convoys" in Iraq if they moved toward the city of Irbil. By Friday morning, the Pentagon tweeted that the military had done just that. This makes Obama the fourth consecutive U.S. president to initiate military action in Iraq.

During the administration of Ronald Reagan, the United States provided material support to Iraq in its war against Iran. Then when Saddam Hussein invaded Kuwait during the presidency of George H. W. Bush, the president authorized military action against Iraq, along with an international alliance of military forces.

On Jan. 16, 1991, Bush announced that the coalition forces had already struck targets in Iraq and Kuwait.

"Just 2 hours ago, allied air forces began an attack on military targets in Iraq and Kuwait. These attacks continue as I speak. Ground forces are not engaged."

A month later, Bush addressed the nation once again, announcing on Feb. 23 that ground forces had begun action in Iraq. He didn't know it at the time, but the ground war would not last long.

In 1993, Bill Clinton assumed the presidency. That April, Bush traveled to Kuwait, where security forces from the country discovered an assassination plot against the former president. In retaliation, Clinton ordered cruise missile strikes against the Iraqi intelligence agency that the United States blamed for the attempt. Here's his announcement, on June 26, 1993.

"This Thursday, Attorney General Reno and Director of Central Intelligence Woolsey gave me their findings. Based on their investigation, there is compelling evidence that there was in fact a plot to assassinate former president Bush. And that this plot, which included the use of a powerful bomb made in Iraq, was directed and pursued by the Iraqi Intelligence Service."

Clinton also inherited control of the leash that coalition forces left on Hussein after the Gulf War: a no-fly zone aimed at protecting Kurdish Iraqis in the northern part of the country and a program intended to ferret out attempts by Iraq to develop weapons of mass destruction. Several times during the course of his two terms, Clinton launched strikes against Saddam for violating one or both of those boundaries.

In 1998, Saddam declared that he would no longer work with the United Nations on the organization's efforts to track its attempts to build a nuclear weapon. On Dec. 16 of that year, Clinton announced that the United States and Britain had struck targets in the country.

"Heavy as they are, the costs of action must be weighed against the price of inaction. If Saddam defies the world and we fail to respond, we will face a far greater threat in the future. Saddam will strike again at his neighbors. He will make war on his own people. ... Because we're acting today, it is less likely that we will face these dangers in the future."

George W. Bush took over the presidency in 2001. Later that year, of course, the terror attacks on the World Trade Center and Pentagon prompted military action in Afghanistan, aimed at removing the Taliban from power and making it more difficult for al-Qaeda to find refuge.

In 2003, Bush announced that the United States would take action against Iraq, too, citing reports of weapons of mass destruction that, he argued, posed a risk to the United States. On March 19, Bush announced that Saddam's failure to leave power meant that the United States and an allied coalition were launching an invasion.

"We come to Iraq with respect for its citizens, for their great civilization and for the religious faiths they practice. We have no ambition in Iraq, except to remove a threat and restore control of that country to its own people. ... Our forces will be coming home as soon as their work is done."

That conflict lasted through Bush's second term and became a focal point of the 2008 presidential campaign. Obama was elected, in part, on his pledge to end the war in Iraq. Over the course of his presidency, he withdrew troops from Iraq and announced that the war had been ended.

On Thursday night, following incursions by the terrorist group Islamic State and the threat posed to both American personnel and ethnic minorities in the country, Obama became the fourth straight president to tell the American people why military action in Iraq was necessary.

In a statement made Thursday night, President Obama said he has authorized military strikes on Islamic State militants if they continue their advancement on the city of Irbil, where military personnel and the U.S. consulate are located. (AP)