Washington (CNN) -- U.S. presidents throughout modern history have developed their own foreign policy doctrines as conflicts around the world tested their leadership.
President James Monroe was the first to articulate a particular doctrine when in his 1823 message to Congress he warned European powers to stay out of affairs in the Western Hemisphere.
Here are some recent presidents' doctrines:
Barack Obama (2009-present)
President Obama, in his speech Monday evening on the United States' involvement in military action in Libya, revealed the beginnings of his doctrine.
The gist: The U.S. can intervene in conflicts overseas "when our safety is not directly threatened, but our interests and values are," he said. Case in point: The potential slaughter of Libyans rebelling against Col. Moammar Gadhafi.
Critics have lambasted the president for not spelling out the mission in clear terms or consulting Congress before deploying the military.
George W. Bush (2001-2009)
"Over time it's going to be important for nations to know they will be held accountable for inactivity. You're either with us or against us in the fight against terror," President Bush said shortly after the 9/11 terrorist attacks.
Perhaps that is the key quote when it comes to his foreign policy doctrine, especially as he took the country to war in Afghanistan and Iraq.
The Bush doctrine ultimately said that the U.S. will not hesitate to act alone, if necessary, to exercise its right right of self-defense by acting pre-emptively against terrorists.
Bill Clinton (1993-2001)
President Clinton, who intervened in the mass genocide in the Balkan region during the 1990s, had a doctrine based on interventionism.
In a February 1999 speech, Clinton said it was in U.S. national interest to stop the fighting and repression in Kosovo before it spread.
"Kosovo, a Serbian province, is not an easy problem, but if we don't stop the conflict now, it clearly will spread and then we will not be able to stop it except at far greater cost and risk," Clinton said.
George H. W. Bush (1989-1993)
In 1990, Iraqi President Saddam Hussein invaded Kuwait -- setting up what would be later known as the Persian Gulf War between a U.S.-led coalition and Iraq.
President Bush immediately condemned the move and looked to gather support from allied countries, including Saudi Arabia.
Bush's doctrine was focused on keeping peace in the Middle East and establishing a new world order.
"The security and stability of the Persian Gulf must be assured," he said during a speech to Congress that year. "And American citizens abroad must be protected. ... Out of these troubled times, our fifth objective -- a new world order -- can emerge: a new era -- freer from the threat of terror, stronger in the pursuit of justice and more secure in the quest for peace."
Ronald Reagan (1981-1989)
Tackling the growing rise of communism by the Soviet Union, which he deemed the "Evil Empire," appeared to be task No. 1 for the Republican president.
His aim: Support anti-communist insurgents throughout the world, especially in Latin America, Asia and Africa, according to the U.S. State Department's website.
"We must stand by all our democratic allies. And we must not break faith with those who are risking their lives -- on every continent, from Afghanistan to Nicaragua -- to defy Soviet-supported aggression and secure rights which have been ours from birth," President Reagan said in his 1985 State of the Union address.
The doctrine, which spanned his two terms in office, also aimed to spread capitalism to the socialist nations.
CNN's Carol Costello contributed to this report.