Running Medi-scared: Furor over Rep. Paul Ryan's (R-Wis.) budget and its changes to Medicare have been the driving issue in this campaign. Hochul points to April 15 as the defining day in her campaign -- the day the GOP caucus overwhelmingly voted for the House Budget Committee's plan that would alter Medicare for future seniors. Democrats recognized the potency of the issue early on. Hochul kept pressing Corwin for her position on Medicare in the days leading up to the vote. When Corwin announced she supported Paul Ryan's plan, Hochul was ready to pounce with an attack ad. Since then, it's been her lead message at every campaign stop. Corwin responded last week with a TV ad clarifying her position, and has been stressing she doesn't think the Ryan plan is perfect and wouldn't support vouchers. But the damage may have already been done. In the Siena poll, a plurality identified Medicare as the biggest issue in the campaign, and of those, 74 percent support Hochul. She's also winning voters over 55 by an eight-point margin over Corwin. The Davis Conundrum. Republicans were more than familiar with Davis, a wealthy manufacturer who was previously the Democratic nominee in 2004 and 2006 - coming with four points of winning the seat in 2006. Each time, Davis made opposition to free-trade agreements almost his only issue - and this time would be no different. But when Lee resigned, Davis interviewed for the Republican nomination instead. When he was passed over in favor of Corwin, Davis began gathering petitions to get on the ballot as an independent - and declared himself a tea party candidate. One problem - local and national tea party groups didn't take too kindly to his self-proclamation and the vast majority endorsed Corwin instead. It's Davis's presence in the race that Republicans point to as the reason for the three-way contest, but a barrage of attacks reminding voters of his past Democratic affiliation have hurt him. Still, his supporters haven't uniformly migrated just to Corwin, and he's still drawing just slightly more support from Republicans than Democrats. Davis has entirely self-funded his campaign, spending $2.6 million of his own money. Republicans outspending Democrats: When a race that was expected to be a sleeper turned surprisingly tight, outside money began pouring into the race. Republican-aligned groups have spent significantly more than their Democratic counterparts. The conservative American Crossroads first sounded the alarm, spending over $700,000 in the race on behalf of Corwin. The National Republican Congressional Committee followed suit, spending nearly $425,000 to attack both candidates. That's in addition to the $2.7 million Corwin's spent herself on the race. The Democratic Congressional Campaign Committee has put $266,000 into the race, pumping up the Medicare message, and the newly-formed outside Democratic group House Majority PAC also has bought ads. Labor has also gone been working heavily on behalf of Hochul. Polls are open Tuesday from 6 a.m. until 9 p.m. ET.