Since the US elections back in November, the 'Trump Trade' has sharply boosted global share markets, based on the promise of lower taxes, less regulation and other 'pro-growth' policies. After a lengthy period of economic 'stagnation' (not quite true), the prospect of Donald Trump ushering-in a thrilling, no-holds-barred period of Reaganesque optimism is an intoxicating idea, no doubt contributing to his election in the first place.
But is all of this about to come unstuck? Quite possibly.
With a Presidency already under fire for possible Russian collusion, bogus wiretapping claims and a myriad of other missteps, you could be forgiven for thinking that you've just stepped out of a time machine and it's 1974 all over again.
Nixon aside, Trump's massively eroded political capital and growing credibility problem points to short-term danger for the sharemarket. If Trump is no longer trusted, or even liked, his capacity to swiftly enact his pro-growth agenda is suddenly at risk, and with it, the quick sharemarket gains made since last November.
And Trump's first litmus test will be tonight's vote on his revised healthcare bill. If the vote doesn't pass or is post-postponed, markets will be rattled. Brace yourself, but don't forget the opportunities that come with uncertainty - we've been here before.