The race to succeed long-time Representative Bill Young of Florida's 13th congressional district who died in October will be decided, as all special elections are, by who can get more of their base supporters to the polls.

But as a preview of the November mid terms, the race probably isn't very relevant.

The Democrats appear to have all the advantages. Alex Sink, Florida’s former chief financial officer and the Democrats’ 2010 gubernatorial nominee, had a head start on the race as she was virtually unopposed in the Democratic primary. Her ability to raise early money was in contrast to Jolly, who had to endure a bruising GOP primary where he emerged with little cash. Sink went to work on Jolly, painting him as anti-Social Security and an extremist. She built a significant lead in a district that has gone from mostly Republican to a swing district in the past decade.

Jolly has been assisted by millions spent by outside groups, who have run some very effective anti-Obamacare ads. The ads and direct mail have helped Jolly narrow the gap significantly to where the latest polls show the Democrat with a slight advantage.

Mail-in ballots may hold the key:

We might get an idea of which way the race is going early in the evening. That’s because, as of Sunday night, 117,000 people had already voted by mail — a figure that could surpass the number who head to the polls Tuesday.

For Sink to win, she’ll most likely need to receive a plurality of support from those early birds. That’s not outside the realm of possibility. Republicans make up 42 percent of those who’ve cast ballots, with Democrats pulling in just behind at 38 percent and independents making up the remaining 20 percent. Democratic operatives, who’ve been drilling down into the early vote figures, are confident Sink can win a strong majority of the Democratic vote, pull a plurality of independents and also peel off some Republican support.

If Jolly wins the mail-in vote, however, Sink’s path to victory narrows. That’s because Republicans — who have slightly more registered voters in the district than Democrats — are likely to be a big percentage of those who cast ballots Tuesday. And those voters are most likely to break Jolly’s way.

Indications are that more Republicans sent in early ballots than Democrats. Whether that translates into a GOP lead by the time those votes are officially counted remains to be seen.

Both sides have been road testing themes and issues that they hope will play well in November. Sink has been backing Obamacare, saying she would fix it. Jolly has called for its repeal. Both sides will be watching how the public responds to the competing narratives about Obamacare:

If Jolly wins on Tuesday, Republicans will certainly say retaining this competitive seat is a validation of their plan to make Obamacare the central issue this fall.

A Democratic victory could have other candidates across the country adopting Sink's approach to discussing health care with a "fix-it" attitude.

House Speaker John Boehner made it clear that even if the Democrats manage to pick up this seat, his party's midterm strategy won't change. Asked if a loss in this special election could alter the GOP message of repealing Obamacare, Boehner replied simply, "No."

Ironically, the race is probably not going to turn decisively based solely on the candidate's views on Obamacare, although the issue may drive more Republicans to the polls today than Democrats, which gives Jolly a decent chance for an upset.

This one probably won't be decided - if at all - until late in the evening.