The glare of a high-profile election has a way of exposing a politician's blemishes.

As Bill Nelson and Rick Scott pour tens of millions of dollars into negative messaging in their neck-and-neck battle for one of Florida's U.S. Senate seats, a clear polling trend has emerged: Both candidates are getting more unpopular.

According to Morning Consult surveys about America's governors and U.S. Senators, both Nelson and Scott have seen their favorability numbers crater in recent months.

In the last quarter of 2017, Nelson had a very healthy +25 net approval rating, according to the Morning Consult survey, which asked over 250,000 voters across the country about their senators. Fifty-one percent of voters approved of the Democrat in that survey, compared to just 26 percent who disapproved.

The same survey taken during the third quarter of 2018 (July 1 through Sept. 25) found that Nelson had a negative overall favorability rating. Just 39 percent of voters approved of Nelson, compared to 41 percent who disapproved. According to that survey, Nelson's popularity fell more between the second and third quarters of 2018 than any other U.S. senator.

Scott also saw a precipitous drop in his popularity numbers between the second and third quarters, according to national Morning Consult surveys that asked hundreds of thousands of registered voters about their governors. The Republican saw his net favorability numbers drop from plus-19 to plus-9 in that time — tied for the steepest drop of any governor.

Read more: Poll: Republicans dominate the list of most popular governors

Other polling showed Scott's net favorability similarly sliding. A July Mason-Dixon poll found that Scott had a healthy plus-11 net favorability rating among 625 registered Florida voters. By late September, Mason-Dixon found that 815 surveyed registered voters equally approved and disapproved of Scott. (Nelson's net favorability fell from plus-five to plus-one in the same surveys.)

There are probably many reasons for Nelson and Scott's dips. The closer we get to election day, the more voters are tuning in and forming opinions of their elected officials. Scott, Nelson and outside groups have also pummeled each other with negative advertising for months. Scott has tried to paint Nelson as a do-nothing senator, and Nelson has tried to claim that Scott is more interested in his personal wealth than in public service.

Which of those messages will resonate more with voters? It may well be that the race for one of Florida's U.S. senate seats may come down to who is less unpopular.