U.S. President Donald Trump poses for a photo with China's President Xi Jinping before their bilateral meeting during the G20 leaders summit in Osaka, Japan, June 29, 2019.

In this multifront, multiyear trade war, with shifting deadlines and political headwinds, it has paid for investors to beware the ides of March. May. August. October. And now, December.

In less than two weeks, President Donald Trump must decide whether to slap tariffs on $156 billion in consumer goods made in China — including toys, phones, laptops and clothes, right before the holidays — or move the goal post yet again in lieu of the comprehensive trade deal he's been seeking.

"If enough substantive progress had been made, he might" be willing to delay, Commerce Secretary Wilbur Ross told CNBC this week. Treasury Secretary Steven Mnuchin said Thursday the two sides were still "on track," for a deal and still talking, but he did not say whether the tariffs would be shelved.

During the Oval Office announcement of the latest truce, Mnuchin assured the public there would be more than enough time to finish the deal and permanently avert further tariffs.

That was two months ago.

Trump now has a complicated calculus to consider: Postponing the tariffs would avoid a market sell-off and higher holiday prices — and the ire of CEOs like Tim Cook and Jamie Dimon whom Trump has come to not only trust but revere. But doing so with anything short of a deal-signing — which Trump said in October was the next step — would mark the fifth instance this year that he delayed or canceled tariffs as a gesture of goodwill, further exposing him to criticism that the "phase one" deal exists only as a talking point.

Enacting the tariffs would cause its own problems. Republicans and Democrats alike would worry the White House was gambling with a U.S. economy already seeing some cracks in its strength. American farmers, many in swing states, would see exports further shrink and endure deeper financial suffering, not to mention continued retaliation.