Remember that Trump lost two tax fraud trials. Both were civil trials, but the evidence was damning and more than sufficient to have justified criminal charges.
Former prosecutors say the Mueller Report shows Trump committed acts "that satisfy all elements for an obstruction charge" including "corrupt intent."
The Mueller Report shows that Trump had motive, method, and many opportunities to obstruct justice, exactly as Nixon did.
Trump promised to release his tax returns, and yet he broke that promise. Now Democrats on the House Ways and Means Committee can help him keep it.