From President Trump’s standpoint, a decline in the World Cup’s popularity due to Ronaldo’s absence would not be pleasant, and the same would be true for FIFA's.
If Trump were to implement his threat, he would, in essence, be Vladimir Putin's partner in crime in a war of aggression that violates international law.
What is clear is that the American judicial system abhors delay. The Americans believe justice must be done fairly, but must also be done swiftly, and they implemented legislation over 40 years ago to do just that.