Despite the tough talk, the Syrian chemical weapons attack poses a particular problem for Trump's foreign policy philosophy.
The attack by Assad's forces offends America's values and it violates long-standing international norms of behaviour, but it does not present an immediate threat to America's security or its economic interests. In an "America First" world, it is an atrocity, but hardly a call to action for the US and its allies.
The President's statement in the Rose Garden suggested that the horrors he had seen on television were causing him to rethink some of the core beliefs he had held about the US role in the world when he was running for office.
The big question was how long Trump's sense of outrage would last and whether it would lead to substantive action.
"The President just made a statement on Assad that looks 180 degrees different from his actual policy," said Kori Schake, a research fellow at Stanford University and former official in the George W. Bush Administration. "This may be a scattershot administration with a president that responds to near-term stimulus rather than long-term planning or strategy."
Less than a week before the chemical weapons strike, Secretary of State Rex Tillerson and UN Ambassador Nikki Haley suggested that the Trump Administration could live with an outcome that wiped out Isis (Islamic State) in Syria but did not remove Assad.
In the immediate aftermath of the attack, Trump seemed to be sticking to that instinct. His first impulse was to focus blame for the attack on President Barack Obama for threatening, but not executing, military strikes when Assad killed hundreds in a 2013 nerve gas attack.
Assad's "heinous actions," Trump said in a statement yesterday after the attacks, were a direct consequence of Obama's "weakness and irresolution".
Sean Spicer, the White House press secretary, played down the prospects of a policy change given the "political realities that exist in Syria".
Today Trump seemed to be hinting - without directly saying it - that Assad's actions must be punished and that the Syrian strongman might have to go.
"I don't have one specific way, and if the world changes, I go the same way," Trump said. "I do change, and I'm flexible. . . . And I will tell you that the attack on children yesterday had a big impact on me - big impact. That was a horrible, horrible thing."
The Trump Administration is in the middle of a major review of its policies in Iraq and Syria that is being led by the Pentagon and Defence Secretary Jim Mattis.
A similar review is underway regarding policy against North Korea, which this week launched another medium-range ballistic missile. The isolated and dangerous regime seems likely to develop a long-range missile capable of delivering a nuclear weapon to the US before Trump leaves office.
Trump, during his Rose Garden appearance, was clearly feeling the weight of both of those foreign policy crises. When asked whether he felt responsibility to respond to the Syrian attacks, he answered affirmatively and then naturally shifted to North Korea and his meeting tomorrow with Chinese President Xi Jinping.
"We have a big problem," he said of North Korea. "We have somebody that is not doing the right thing, and that's going to be my responsibility."
Whether that burden will push Trump away from his "America First" outlook and towards a more traditional foreign policy remains to be seen. In just his few months in office, Trump has consistently upended foreign policy norms and shown that he has little interest in leading or enforcing the rules-based international order as other presidents had done over the past 70 years.
For the moment, the biggest changes from the Obama years are in style and rhetoric. Trump often has seemed more ambivalent than outraged over Russia's invasion of Ukraine and its annexation of Crimea. His interest in Nato, the cornerstone of security in Europe, is often largely confined to whether the allies are paying their fair share and the US is getting a good deal.
He has shown a clear preference for stable dictators over the spread of democracy as indicated by the warm Oval Office welcome given to Egyptian President Abdel-fatah al-Sisi, who was shunned by the Obama White House for his brutal crackdown on dissidents.
The Syrian chemical weapons attack seemed to awaken Trump's sense of moral responsibility as leader of the world's sole remaining superpower. A president who has often seemed indifferent to suffering in faraway countries - including the plight of Syrian refugees - reacted with a natural revulsion.
Less clear was whether that revulsion would produce a significant shift in policy.
"I'm still trying to sort out what the reactions of the White House are and whether they have changed their position on Assad or whether it's just a rhetorical shift," said Danielle Pletka, a vice-president at the American Enterprise Institute, a conservative Washington think-tank.
Other analysts echoed that confusion. "They have not yet figured out what they are trying to do," said Peter Feaver, a professor at Duke University and an adviser in the second Bush Administration. "What looks like recalibration might be multiple voices."
In a White House marked by rival factions, it has become difficult to figure out who exactly is in charge of foreign policy. Today, Trump removed White House chief strategist Stephen Bannon from the National Security Council. The change suggested that national security adviser H.R. McMaster, who has a traditional view of US power and global leadership obligations, was gaining influence over policymaking.
For his part, Trump left many guessing about his ultimate intentions in Syria and North Korea. "I don't like to say where I'm going and what I'm doing," he said.
His broader view of foreign policy, though, was clearer and unchanging.
"I just have to say that the world is a mess," he said. "I inherited a mess."
