Pence can absolutely pardon Trump for violating the money laundering laws. All he would have to do is claim that the spectacle of a past President on criminal trial would be against the national interest, and an unsurprisingly large number of Americans would agree. Trump still has a 40% approval rating, and that is not likely to go down much further.
Trump can only be pardoned for violations of federal law i.e., offenses against the United States.
A President’s clemency power is conferred by Article II, Section 2, Clause 1 of the Constitution of the United States, which says, "The President ... shall have Power to grant Reprieves and Pardons for Offenses against the United States, except in Cases of Impeachment.”
So the President’s authority to grant clemency is limited to federal offenses and offenses prosecuted by the United States Attorney for the District of Columbia in the name of the United States in the D.C. Superior Court.
An offense that violates state law isn't considered an offense against the United States. Otherwise, we could end up in federal court for a speeding ticket.