In Trump's tweet he referred to the F-35 program from Lockheed Martin, which makes the F-35 Joint Strike Fighter. This prompted the entire defense sector to get hit hard, with Northrop Grumman closing down 2.6 percent and Raytheon 1.7 percent on Monday.
The question for Cramer was if the President would even have the ability to drive down the cost of the jet. Until a few weeks ago, Cramer assumed that a promise to "drain the swamp" was merely campaign rhetoric and Trump wouldn't be involved in the actual jawboning of companies to get what he wants.
That all changed when Trump called United Technologies CEO Greg Hayes to convince him from exporting Carrier jobs to Mexico. Hayes said he got the message from Trump and said he was born at night, but not last night.
No threat necessary.
Then there was the tweet over the New Air Force One, and Boeing's CEO Dennis Muilenburg agreed to talk to Trump about lowering the cost of two planes the government ordered.
Last week there was also Time Magazine's "person of the year" interview, when he took aim at drug prices.
There is a clear pattern here to Cramer.
"If a company relies on the government for a big chunk of its business, that revenue stream is now in jeopardy," Cramer said.
That is why Cramer wants investors to be prepared for the new risks that Trump has introduced to the market.
"He's not just a tweeter in chief, he's a negotiator in chief, and right now, at least, he seems to hold all of the cards," Cramer said.