In a tweet on Monday, Pickens wrote "Negotiating advice 101. When you want to make a deal real bad you will make a really bad deal. #SingaporeSummit."
Pickens' longtime spokesman, Jay Rosser, said the tweet wasn't meant to be critical of Trump. He said his boss only hopes the president isn't too desperate to come to an agreement with the North Korean dictator during their historic summit.
"Look, if you go into a deal, and you are going into it with a sense of desperation — of course, the U.S. isn't — but if you do have that sense of desperation, you're certain to make a lousy deal."
Pickens chaired energy hedge fund BP Capital Management from his Mesa Vista Ranch. He recently shut down the operation after health and financial setbacks.
He's also become a prominent donor and fundraiser for the Republican Party.
During the 2016 election, he gave $100,000 to the Senate Leadership Fund, a super PAC dedicated to maintaining a GOP majority in the Senate. He donated hundreds of thousands to the Republican National Committee, the National Republican Congressional Committee, and House Majority Leader Kevin McCarthy's Victory Fund, among others, Federal Election Commission records show.
He did not, however, contribute to Trump's campaign.
So far in the 2018 election cycle, he's given very little, with only $10,000 going to McCarthy's fund and just over $14,000 being spread to other PACs as well as congressional races. He has not donated to Trump's re-election committees.
Still, though Pickens is not making it clear with his checkbook, Rosser insisted that Pickens supports the president.
He pointed to a fundraiser that Pickens hosted in October 2017 for the pro-Trump America First Action super PAC, a group run by longtime Dallas financer Roy Bailey. Donald Trump Jr. attended the event, Rosser said, along with Bailey and many other contributors.
He also noted there are no immediate plans to host a fundraiser for the president's re-election committees due to ongoing health concerns.