You won't find liberals questioning election outcomes that were determined by a margin of thousands of votes with a clear paper trail. The 2000 election in Florida, which you're probably thinking of, involved just a few hundred votes where the intent of the voter wasn't super clear (hence the "hanging chads" brouhaha); and once the election outcome was finally determined, liberals let things go. While they disagreed with the procedure and were upset about the outcome for a while, they didn't let it define their party for the next 4+ years.