If we assume that you are correct that there are campaign finance violations by Trump that need to be pursued, then let's have a look at campaign violations that Obama was convicted of and that his campaign was fined $375,000 for to see what happens when a presidential candidate violates campaign finance laws:
Obama 2008 campaign fined $375,000 for $2,000,000 in illegal campaign contributions
Campaign finance violations are typically treated as administrative violations by the campaign that is handled with a fine, paid by the campaign, and not the candidate.
If Trump defrauded the American electorate with $280,000 in improper campaign contributions, then so did Barack Obama, and even more so with his $2,000,000 of improper campaign contributions.