As Florida holds its primary today, the Senate race there is emerging as a potential bright spot for the GOP in an otherwise dismal-looking year. The Republican challenger’s lead in the polls is surprising, but will it last? I’m skeptical, but would not rule it out.

The Florida GOP, like most Southern Republican parties in peripheral Southern states, grew out of the increased urbanization of the South in the 1940s and 1950s. Republicans won their first seat in Congress in the Tampa/St. Petersburg area in 1954, as northerners moved down and brought their Republican voting habits with them. In 1962, similar shifts moved the “Space Coast” toward the GOP, while central Florida and Broward counties followed in 1972. In 1968, Republican Edward Gurney defeated Democrat LeRoy Collins by 12 percentage points to claim the seat of retiring Democratic Sen. George Smathers.

As with most states, there was a two-steps-forward/one-step-back element to the GOP’s advance across the state. Edward Stack won back the Broward County seat for the Democrats in 1978 by over 20 points, while a young Democrat named Bill Nelson captured the open Space Coast district by 22 points.

But the GOP’s progression was palpable, and by 1990 a tectonic shift seemed inevitable. While Democrats held their own in the northern portion of the state (in Florida, the saying goes, you have to go North to go South), the increasingly suburban areas voted Republican, and the influx of Cuban refugees made the southern tip increasingly hospitable to the Republican Party. Yet Nelson never had a truly competitive race during his House tenure. He resigned to run for governor in 1990, a race he lost to Lawton Chiles.

Nelson won election as state treasurer in 1994, and was re-elected in 1998 as the GOP continued to post wins in the state. Yet Florida was also in flux; the suburban gains made by the GOP began to work against them in the ’90s. As recently as 1988, George H.W. Bush won the state by 22 points, but Bill Clinton’s reputation as a moderate Democrat enabled him to flip counties like Pinellas and Palm Beach to the Democrats. These counties voted Democratic in 1992 for the second and first time since 1944, respectively, as Clinton shifted the voting patterns of northern suburbs, losing narrowly to Bush (H. Ross Perot siphoned off 19 percent of the vote). In 1996, he carried the state outright.

Since then, Nelson’s career has been blessed by badly flawed GOP opponents; he is one of a handful of Democrats to win statewide office since 1998. In 2000, he faced uncharismatic Republican Bill McCollum, en route to a five-point victory as Al Gore and George W. Bush were locked in a historically close struggle for the state. In 2006, he benefited from the anti-GOP wave and an opponent guaranteed to energize the Democratic base in Secretary of State Katherine Harris, who had overseen the contested 2000 election. He won by 22 points. In 2012, he faced Connie Mack IV, who ran an underwhelming campaign and was dogged by allegations of road rage and an arrest for a bar fight. Nelson won by 13.

This year could be different. Nelson faces a solid Republican in Gov. Rick Scott. While Scott has been unpopular for much of his tenure and only narrowly won the governorship in GOP wave years, his job approval has improved and now is in the high 50s. During Hurricane Maria, Scott made himself a near fixture in the Puerto Rican community; polling shows him performing unusually well among that subpopulation. Scott is also wealthy, and can spend freely in the election; he has been pounding Nelson on the airwaves.

This is evident in the polls. Scott has led Nelson in most recent polls, and is currently up by 1.5 points in the RCP Average. In fact, Nelson has led in only two polls since February. The 75-year-old incumbent has the disadvantage of a lifetime association with Washington, D.C., which is as unpopular as ever, and it is unclear that he is prepared for what is likely to be the first serious re-election contest of his life. Nelson is low-key and cuts a low profile at home, which lends credence to charges that he is ineffective.

If this were an environment like 2010 or 2014, Nelson would likely be an underdog, perhaps heavily so. But it is decidedly not. The president has weak approval ratings nationally. There is probably no state that has followed national trends as closely as Florida. Since 1992, Democratic presidential candidates have won a total of 24,140,463 votes in the state, while Republicans have won a total of 24,122,710 votes, a difference of 17,753 votes, or about 2,500 per election (thanks to Steve Schale for pointing this out).

The point is that the president is likely unpopular here, and there is a longstanding tendency for senators to run roughly even with the job approval of their presidents. For Scott, we would expect him to probably win somewhere between 44 and 46 percent of the vote with the president at 43 percent nationally.

This also happens to be roughly where the polls show Scott polling. In other words, he has likely locked down the vast majority of Trump supporters and undecideds. The remaining pool is probably not particularly fertile soil for him. Moreover, as a well-known statewide officeholder, he is something of a de facto incumbent, especially against a lower-profile Democrat like Nelson.

The bottom line is that Scott might be at something of a ceiling. This is consistent with what we saw in 2014, where many Democrats had leads throughout the year, but never saw their vote shares increase. As a classic example, in the Thom Tillis-Kay Hagan race in North Carolina, Hagan was up by around six points in September of 2014, but her 46 percent support then almost exactly matched what she received on Election Day; undecideds overwhelmingly broke against her.

None of this is to say Scott can’t win; he very much can. It is merely to say that the polls are probably overstating his strength, and he probably needs to get his poll average up to around 48 percent for a lengthy period of time before he really starts to feel good about this race.