For Connecticut Republicans, the gubernatorial primary was a five-way slug fest. For Democrats, it was more of a coronation.

But now that both parties have selected their candidates, it remains to be seen whether Republican Bob Stefanowski can defeat Democratic candidate Ned Lamont in a race generally considered a toss-up.

On Aug. 14, Stefanowski, a business executive won the Republican primary with 29.4 percent of the vote. He beat party-endorsed candidate and Danbury Mayor Mark Boughton, who garnered 21.3 percent of the vote, as well as businessmen David Stemerman and Steve Obsitnik, who received 18.3 and 13.4 percent, respectively, and former Trumbull First Selectman Tim Herbst, who took 17.6 percent.

“This campaign has been underestimated from the start,” said Stefanowski in a speech following his primary win. “But we’ve proved them wrong, and we’re going to prove them wrong when we beat Ned Lamont in November.”

Many pundits and experts called Stefanowski’s primary victory an upset. But Gary Rose, chair of the Department of Government at Sacred Heart University and a frequent gubernatorial debate panelist, said he sees it as anything but.

“It’s not a surprise that Stefanowski won,” he said. “The Republican party in the state of Connecticut is enamored with businesspeople.” Rose pointed to Tom Foley, the 2010 and 2014 Republican nominee for governor, and Linda McMahon, the 2010 Republican nominee for senator, as past business executives who have won statewide Republican primaries.

Rose and political columnist Chris Powell both said that Stefanowski’s massive head start in advertising played an important role in his primary victory. Stefanowski began heavy TV advertising well before any of the other Republican gubernatorial candidates, spending his own money while other candidates were mired in the process of securing public funding. The Campaign Finance Institute, a nonpartisan, peer-reviewed think tank that focuses on money in politics, reports that Stefanowski has given $2,073,906 to his primarily self-funded campaign. For his part, Lamont has donated more than $800,000 to his own campaign.

Over the course of the campaign, Stefanowski’s advertising proved effective, as he successfully cast his main competitor Boughton as a “liberal loser.” Rose said the combination of those attacks and voters’ desire for new faces turned the tables in Stefanowski’s favor.

Democratic nominee Lamont, a Greenwich entrepreneur and a candidate for the U.S. Senate in 2006, won the Democratic primary with 81.2 percent of the vote. Endorsed by the Connecticut Democrats at their May convention, Lamont was the clear favorite to win the nomination. His only competition, Bridgeport Mayor Joe Ganim, took the remaining 18.8 percent of the vote in the August primary.

The victories of both Stefanowski and Lamont set the stage for a competitive general election. Although recent polling has placed Lamont in the lead, a spokesman for the Republican Governors Association — a national organization focused on electing and supporting Republican governors — told the Hartford Courant on Monday that Connecticut is the party’s best chance to win a governor’s seat currently occupied by a Democrat. The same association also committed $1.7 million toward TV advertising for the winner of the Republican nomination.

Ultimately, Rose said, this race will come down to taxes and jobs. Connecticut’s billion-dollar deficit and general financial woes have left the state in disarray, and both candidates for governor have proposed various fiscal solutions.

“The real nitty-gritty, meats-and-potatoes-type issues are forming the nucleus of this debate,” Rose said.

Lamont has promised to lower property taxes after resolving the budget deficit, which he hopes to accomplish by reducing the prison population, collecting revenue from sports gambling and improving tax collections.

Powell, however, said he is not convinced these measures are enough to resolve the eventual $2 billion deficit. “If there really was any money in those proposals, the legislature would commandeer them,” he said.

Stefanowski has proposed eliminating the state income tax over an eight-year span under the rationale that it would attract business to Connecticut. Although Powell said the plan would eliminate half of the tax revenue the state currently collects, Rose described this plan as a “boon” for Stefanowski’s popularity that drove up his primary vote total.

Stefanowski agreed to four televised debates to discuss these issues: Sep. 12 in New London, Sep. 26 at the University of Connecticut, Oct. 18 at a Connecticut Broadcasters Association forum and Oct. 30 at a Connecticut Conference of Municipalities event. Stefanowski declined an invitation to a fifth debate, labeled an economic forum, on Sep. 5 at the University of St. Joseph.

Third-party candidate Oz Griebel, who qualified for the ballot this week after obtaining the requisite number of signatures, will participate in the Sep. 5 debate with Lamont.

Voters will choose Connecticut’s 89th governor on Nov. 6, 2018.

Conor Johnson | conor.johnson@yale.edu