ANALYSIS: President Trump redefines own doctrine with Syria strike The president showed he is willing to move quickly on military action.

 -- This wasn’t the kind of presidential action Donald Trump supporters expected to see. It may not even be the kind of action President Trump himself expected to take.

Trump’s decision to launch swift and targeted strikes against Syrian assets amounts to a redefinition of his foreign policy and national security agendas. It sends a message to Trump’s allies and adversaries, both at home and abroad, that a freewheeling president will move in stark, quick, and perhaps unpredictable ways – even while conforming to broad understandings of the appropriate uses of American power.

It demonstrates that the president does not intend to be constrained by his own previous statements or positions when deciding how to act. And it signals to a world that’s skeptical of an untested president that the Trump doctrine will include American action that has little precedent in terms of its speed – a clear break with the international deliberations favored by the last administration.

“President Trump is willing to act when governments and government actors cross the line,” Secretary of State Rex Tillerson told reporters shortly after the air strikes were conducted Thursday night. “President Trump made that statement to the world tonight.”

This would appear to be the kind of military engagement Trump suggested that he would avoid as president. His Twitter feed is littered with warnings against President Obama using air strikes or other means to attack Syria, suggesting that he needed congressional authorization and that American interests would not be advanced by intervening.

With the president’s “America first” slogan and intellectual guiding force Steve Bannon in a top position, the idea of foreign entanglements has drawn scorn from the Trump crowd. One of the few times in the campaign Trump broke publicly with his running mate, Mike Pence, came after Pence appeared to back intervention in Syria, when he said the U.S. “should be prepared to use military force to strike military targets of the Assad regime.”

“He and I haven't spoken, and I disagree,” Trump said at a presidential debate the following week. “Syria is no longer Syria. I believe we have to get ISIS. We have to worry about ISIS before we can get too much more involved.”

Yet Trump did choose to get involved this week, driven by shocking images of a chemical attack’s aftermath, and a sense that Assad was testing Trump’s resolve.

The decision raises profound questions about Trump’s strategy regarding Syria and Russia, including whether to support regime change, as well as what criteria he plans to use when deciding whether and how to use military force. Assad retrains his grip on Syria, and he won’t be the last head of state to test Trump.

The move may also strain the president’s ties with elements of his base. For libertarians and others in both parties, Trump’s unilateral attack raises troubling questions. Some of his fellow Republicans - notably Sen. Rand Paul, a former rival for the presidency – are among those demanding congressional action before further steps are taken.

But whether Thursday’s orders end up as a one-off, or the start of more sustained involvement in Syria, the move itself was something that a President Marco Rubio or a President Hillary Clinton might have made themselves.

That leaves Trump in unfamiliar, if precarious, territory. After a loud Thursday night, he enjoyed a relatively quiet Friday, owing to a touch of bipartisan consensus about the step he took.

He may well reap political rewards for his actions. Yet extrapolating the latest events into future actions is much like reading the president’s words for guidance – a fraught exercise, perhaps more than ever.