Florida Senate Seat Becomes Year’s Most Expensive Race

Mr. Nelson is one of 10 Democratic senators up for reelection in states President Trump won in 2016, although the president captured Florida only by less than 2 percentage points.

For Democrats to flip Republicans’ 51-49 Senate majority, they need to hold all 26 of their seats up for reelection and win two of the nine GOP-held seats. That prospect has dimmed recently with improved Republican polling in battleground states like Tennessee and North Dakota.

Most midterm elections this year are seen as a referendum on Mr. Trump, but in Florida neither candidate has made him central to their message.

Mr. Scott, unlike other GOP candidates in red states like Montana and North Dakota who have spotlighted their ties to the president, has kept a distance from him. One closing Nelson ad portrays Mr. Scott as a Trump yes man and asks, “Who has the independence to put Florida first?”

Mr. Scott rejects the claim that he won’t stand up to Mr. Trump. “When I think it’s good for Florida, I’m going to work with him,” he said in an interview. “If I disagree with him, I’m going to disagree with him.”

He has appeared with Mr. Trump at official events but not at the president’s campaign rallies. Mr. Scott said he hasn’t decided whether to join the president at his rally next week in Fort Myers, saying he is still focused on hurricane relief.

With Florida’s costly media markets, the Senate race is the most expensive of the year, with $136 million spent as of Oct. 25, including $70 million by the candidates and $66 million by outside groups, according to analysis of Federal Election Commission reports by the nonpartisan Center for Responsive Politics.

Mr. Scott, 65, who cannot seek a third term as governor, is running on his record of presiding over steady economic growth and, lately, his response to hurricanes. He says that the 76-year-old Mr. Nelson, who is seeking his third Senate term, has stayed in Washington too long and accomplished too little.

Mr. Nelson says his Senate seniority has reaped benefits for the state. He says that Mr. Scott’s health policies would put people with pre-existing conditions at risk of losing affordable insurance.

“We’re at an important inflection point right now,” said Mr. Nelson at a rally in Orlando with former Vice President Joe Biden. “Now more than ever folks in Florida need somebody they can trust. They need public servants that know right from wrong.”

Ever since Hurricane Michael hit the Panhandle more than two weeks ago, Mr. Scott has stepped off the campaign trail to lead the recovery. He has been sending surrogates including his wife and GOP officials to campaign events, such as one in Hialeah as early voting began this week.

Lt. Gov. Carlos López-Cantera raised concern that GOP turnout in the Panhandle would be down in the wake of Hurricane Michael. “There are Republican voters in northwestern Florida that normally we can count on that won’t be able to vote this year,” he said in Spanish. The eight hardest-hit counties were won by Mr. Trump in 2016 by landslide margins, some with over 77% of the vote.

Faced with widespread destruction in the region, including of some polling facilities, Mr. Scott issued an executive order that authorized supervisors of elections there to extend voting options—by adding early voting sites, for instance, or extending the early voting period.

He has swayed voters like Dolores Hernández, 78, a Republican retired food worker, not just for his response to Michael but also to Hurricane Maria last year in Puerto Rico. “He has always been present and sent a lot of help,” she said. However, Puerto Rican Gov. Ricardo Rosselló endorsed Mr. Nelson.

Environmental concerns have been a major issue in the campaign because of an outbreak of blue-green algae and red tide, which produces toxic chemicals blamed for killing fish, sea turtles, dolphins and other animals. The current red tide has lasted about a year so far, the longest stretch in more than a decade, and has spread from the west coast to the east, hurting the tourism industry.

Mr. Scott pins blame for the algae problem on Mr. Nelson, for failing to secure federal aid to address it. But as chief executive, Mr. Scott has been thrown more onto the defensive. At a campaign stop in Venice in September, protesters criticized the governor’s environmental record and chanted, “Red tide Rick has got to go.” He ended up leaving the event through a back door.

The issue motivates voters like Mary Montanus, an Orlando retiree. “A lot of people blow off the midterm elections, but this year I don’t think anyone should blow it off,” she said outside an early voting location. “This year it’s an extremely critical time for the environment.”

The state’s gubernatorial campaign pits conservative Republican Ron DeSantis, a 40-year-old former House member, against progressive Democrat Andrew Gillum, mayor of Tallahassee.

Polls show Mr. Gillum, a 39-year-old African-American, is favored to win. He is regarded as an asset to Mr. Nelson because he is expected to boost turnout among Democratic voters who tend not to vote in midterms—young people and people of color.

Arianna Moss, an 18-year-old registered Democrat in Miami, said she doesn’t follow politics much, but that there is a lot of buzz among her friends about Mr. Gillum. “That’s why I voted for him” as well as other Democrats, including Mr. Nelson, she said. “We hear so much about him.”

Mr. Scott could benefit from increased turnout among strong Trump supporters who are backing Mr. DeSantis, who was endorsed by the president in the GOP primary.

“I voted for Trump in 2016. I’ll vote for him in 2020. I’ll vote for people who support him in 2018,” said Dean Mannino, an Orlando construction manager, after voting early for Mr. Scott and Mr. DeSantis.

Write to Janet Hook at [email protected] and Arian Campo-Flores at [email protected]