He could push for probes of consumer protection, privacy and antitrust issues. He could also step up his support for allowing states to collect sales tax on third-party purchases from Amazon, or seek to have the Postal Service charge more to deliver packages. And he could thwart Amazon’s aspirations to win a multibillion dollar Pentagon contract for cloud services.

Even with those powers, Trump’s ability to act has limits. Inquiries by the Justice Department or the Federal Trade Commission could take years and bear a high burden of proof. The FTC and other enforcement agencies guard their independence, as does the board of governors of the Postal Service. Changes to the tax law would require cooperation from Congress, which just passed a tax overhaul and may have limited appetite to reopen negotiations.

The feud pits the world’s most powerful man against one of the world’s biggest corporations -- a global titan with $684 billion in market capitalization and more than half a million employees. At stake is its reputation, revenue and, potentially, ability to continue to disrupt markets as it reshapes retailing.

Any move made by Trump that is perceived as revenge against Amazon founder Jeff Bezos for his ownership of The Washington Post would invite comparisons to President Richard Nixon, who, at the height of the Watergate scandal, threatened the Post’s broadcast licenses.

Amazon didn’t respond to a request for comment. While Amazon rose Thursday along with most U.S. stocks, the Trump attacks helped add to the shares’ headwinds on Tuesday and Wednesday. An 8 percent drop marked Amazon’s biggest two-day decline in two years.

White House spokeswoman Lindsay Walters told reporters aboard Air Force One Thursday that there are no specific plans to move against the company. “The president has expressed his concerns with Amazon," she said.