Jeet Heer says no:
[T]he very nature of our modern world, and the United States’ supremacy, makes it impossible to dismiss an American president’s word. The U.S. is a nuclear-armed superpower, with a commander in chief who presides over the world’s largest economy. Millions of people all over the world pay careful attention to what a president says, making their own plans based on the words coming out of the White House—and they will continue to do so whether or not the press corps and political class in Washington somehow agree en masse to ignore Trump’s tweets.
“Toyota Motor said will build a new plant in Baja, Mexico, to build Corolla cars for U.S. NO WAY!” Trump tweeted in January. “Build plant in U.S. or pay big border tax.” Toyota’s stock promptly fell, as has the stock of other companies caught in Trump’s Twitter crosshairs. Because his tweets move markets, businesses are developing strategies for how to handle a presidential social media attack. There’s even an app that lets you know when Trump has tweeted negatively about a publicly traded company, so you can sell quickly if needed. Another company created a lightning-fast Twitter bot that automatically short sells such stocks. It’s called “Trump and Dump.”
“Mr. Trump’s Twitter posts, viewed with amazement outside the West Wing bubble, often create crises on the inside,” the Times reported. “That was never truer than when Mr. Trump began posting from his weekend retreat at his Mar-a-Lago estate in Florida shortly after sunrise on Saturday. His groggy staff realized quickly that this was no typical Trump broadside, but an allegation with potentially far-reaching implications that threatened to derail a coming week that included the rollout of his redrafted travel ban and the unveiling of the Republican plan to replace the Affordable Care Act.”
The more one watches this clown, the more one wonders just how much he's a genius, or, you know, something else?