Let's look at the '92 race first. Mikulski Mikulski beat Ross Pierpont, her GOP challenger in 1998, too. Mikulski outspent Chavez about 6-5. Next time, as an incumbent, Mikulski outspent Keyes over 3-1. Pierpont, who tried next, in 1998, couldn't do any better than Keyes did in '92, though he had no worries from having Clinton at the top of the Democratic ticket.
Keyes certainly does no worse than the other two candidates.
Clinton was not on the ballot, and if he had been, it might not have helped the democrats. Clinton was in bad odor in those days, because the GOP, showing some backbone, had stood up to and defeated his health care project. A former U.S. Trade Representative, Republican National Committee Chairman, and United States Senator, Bill Brock ran for the Maryland Senate seat. Brock outspent Sarbanes about 3-2. I have only given the numbers for the last two elections.