The chaos and bombast that have driven President Donald Trump's White House into its deepest crisis just burst America's borders.

Trump's sudden announcement Thursday of punishing tarrifs on steel and aluminum imports, after a typically disorganized and opaque rollout, left much of the world feeling the whiplash that has rocked Washington all week.

"What's been allowed to go on for decades is disgraceful. It's disgraceful," Trump told reporters, delivering a sudden shock to the global economy by saying he would unveil tariffs next week of 25% on steel and 10% on aluminum.

World powers now know what it's been like for Trump's fellow Republicans and staff in a week of turmoil and neck-jerking policy pivots that have left them groping for clarity and trying to work out exactly where the President stands.

At home, stocks crashed on the President's offhanded announcement, which could blow up into a trade war, while GOP leaders, stung by a second straight day of Trump trampling party orthodoxy after his surreal meeting Wednesday on guns, registered dissent and frustration.

"We were told at the beginning of all this that Donald Trump was comfortable with chaos -- that's how he is accustomed to operate," David Axelrod, a former Obama administration top strategist, said on CNN's "The Situation Room."

"That may be OK if you are running a small family branding business, but when you are in the most important office on the planet it can have grave consequences," Axelrod said.