Countdown to a crisis:

Inside Trump’s war room

President Donald Trump first saw the photos Tuesday morning.

The images were ghastly. Men and women gasping for breath. Small children foaming at the mouth and in agony. The lifeless bodies of babies sprawled on the ground.

This was the aftermath of a chemical attack ordered by Syrian President Bashar al-Assad, who the US would soon conclude had unleashed sarin gas, a brutal nerve toxin, on his own people. The president peppered his advisers with questions, according to national security adviser H R McMaster, who later said Trump was immediately focused on getting to the bottom of “who was responsible”.

By the end of the briefing, the president had dispatched his team to draw up options for a response.

The leap to considering intervention was remarkable. In 2013, Trump had argued against military intervention in Syria when it was President Barack Obama’s decision to make. He had hardly portrayed himself as a humanitarian crusader on the campaign, when he adopted the slogan “America First”.

Just last week, the White House declared itself resigned to the status quo of a Syria led by Assad. It was “a political reality that we have to accept”, White House spokesman Sean Spicer had said.

But as Trump spent Tuesday in meetings about the nation’s business climate and his infrastructure plan, the images from Syria weighed on him, his aides said. He was disturbed by images of “babies”, some the ages of his grandchildren.

Tuesday evening the National Security Council’s Deputies Committee briefed Trump with options, a meeting that set in motion a new president’s startling transformation from resigned to resolved to act.

WEDNESDAY

Under the spring sunshine in the Rose Garden, 24 hours after his first briefing on the chemical attack, Trump was asked what he thought.

Standing next to King Abdullah II of Jordan, the typically blustering president was unusually grave.

He revealed his horror, saying the images “of innocent children, innocent babies” killed by poison gas were causing him to rethink his approach on Syria.

“It’s very, very possible, and I will tell you it has already happened, that my attitude toward Syria and Assad has changed very much,” Trump said. The attack “crossed a lot of lines for me”.

“I now have responsibility,” Trump said, “and I will have that responsi- bility and carry it very proudly.” Later that afternoon, Trump convened a meeting of his top national security advisers to review three options ranging in levels of risk and scope. The details on each are not clear. But a US official with knowledge of the proposals said one plan would have targeted a number of chemical weapons sites, a move that would