The previous three Republican presidents took the United States to war during their first term in office.
President Donald Trump has yet to follow suit – but his time at the helm has been far from peaceful.
He is locked in an escalating trade war with China and wars of words with Iran, North Korea and Venezuela.
The US military is also continuing to fight – at times expanding their role – in operations that the president inherited in Iraq, Syria and Afghanistan, as well as interventions elsewhere.
He even did what his Democratic predecessor Barack Obama balked at doing in Syria by launching cruise missile strikes, on two occasions, against the regime of President Bashar al Assad after it deployed chemical weapons against its people.
By the same point in his presidency, George W Bush, a fellow Republican, had already taken the US to war against the Taliban and al Qaeda in Afghanistan following the September 11 terrorist attacks against his country in 2001.
His administration had also just launched the US-led war against Saddam Hussein in Iraq, declaring “mission accomplished” prematurely in the May of his third year as president.
For his father, George H W Bush, who served as president for a single term from 1989 to 1993, conflict came in the form of the First Gulf War, when US forces led operations against the Iraqi president for a first time after Saddam invaded Kuwait in 1990.
Ronald Reagan, on a much smaller scale, authorised the US invasion of Grenada in 1983, citing a threat posed to US nationals living on the Caribbean island by Grenada’s pro-Marxist regime, at a time when the Cold War was still running hot.
Operation Urgent Fury, which only lasted a handful of days, brought about regime change.
It’s not just Republican presidents who have embarked on new, sustained military operations during their first four years at the White House.
Mr Obama took charge at a time of growing criticism over US interventions in Iraq and Afghanistan.
But two years into his first term, he agreed to support a military intervention in Libya that was being pushed for by Britain’s David Cameron and Nicolas Sarkozy of France.
The United States, because of its superior firepower, took the lead in the first few days of the air campaign against Muammar Gaddafi’s forces in March 2011, before NATO stepped into the leadership role.
Bill Clinton, an earlier Democratic president, also committed US forces to NATO-led operations during the Bosnia war in the early 1990s.
He went on to play a pivotal role in the Kosovo war, which took place during his second term.
A number of challenges could yet trigger new interventions for Donald Trump over the next 20 months despite his “America First” mantra and desire to pull troops out of conflict zones.
Warnings by the US of an unspecified threat from Iran have prompted the deployment of an American aircraft carrier strike group, B-52 bombers, a Patriot missile defence battery and an amphibious warship to the Gulf in the past few days.
Tensions between Tehran and Washington are mounting as a deal that helped to curb Iran’s nuclear ambitions unravels.
A number of challenges could yet trigger new interventions for Donald Trump over the next 20 months despite his ‘America First’ mantra and desire to pull troops out of conflict zones.
Hopes of a peace accord between North Korea’s Kim Jong Un and Mr Trump have faced a setback after a second summit ended without agreement.
This was followed by the provocative test firing of missiles by the North Korean regime.
And a rift is growing between the United States and the Russia-backed government of Nicolas Maduro in Venezuela – another potential flashpoint.
For now, though – and perhaps against the odds – President Trump remains a Republican commander in chief who has not started a new, hot war.