(CNN) Wisconsin Republican Sen. Ron Johnson will win reelection, CNN projects, defeating Mandela Barnes in a race that Democrats saw as one of their best flip opportunities in the midterm elections.
The victory is another demonstration of the remarkable political durability of Johnson, 67, who has now won three consecutive hard-fought elections, despite polls that long showed him among the least popular senators up for reelection this year.
In holding off Barnes -- whom Democrats had viewed at the outset of this year's election cycle as a potential rising star -- Johnson has also bolstered the GOP's hopes of winning control of the Senate.
Barnes conceded and thanked supporters on Wednesday.
"We didn't get over the finish line this time. But I know this movement that has meant so much to all of us will keep going," he said in a statement.
Throughout the summer and fall, Republicans relentlessly focused their attacks on Barnes over crime.
The attacks focused on Barnes' efforts as a state lawmaker to end cash bail, as well as a 2020 interview with PBS Wisconsin -- weeks after the police killing of George Floyd in neighboring Minnesota -- in which Barnes suggested that funding should be redirected from police budgets to other social services.
The GOP seized on the trial of Darrell Brooks, the man who was found guilty of six counts of first-degree intentional homicide in late October for driving his SUV into a crowd of Christmas parade attendees in Waukesha, Wisconsin, last November, killing six people and wounding dozens more.
Brooks was out on $1,000 cash bail when he committed the murders. Barnes had been a chief proponent of bail reform as a state lawmaker. But he argued that his measure would have kept potentially violent offenders like Brooks in jail.
Barnes' slim lead in public polls collapsed in September, when Republicans spent nearly $6 million more than Democrats on the air slamming Barnes, primarily on crime. By October, a CNN poll conducted by SSRS found no clear leader in the race.
Barnes, the lieutenant governor of Wisconsin, meanwhile, focused on Johnson's role in the events surrounding the January 6, 2021, attack on the US Capitol.
Johnson, who played a role in trying to push "fake electors" for then-President Donald Trump before the start of the congressional certification of the 2020 electoral votes, has repeatedly downplayed the attack on the Capitol, saying it was not an "armed insurrection," including as recently as October.
Johnson's campaign kept his schedule limited and rarely advised reporters about events. Instead, he campaigned largely through Fox News appearances such as one on Sean Hannity's program in October, in which he said: "My fundraising is weaker. I rely on your audience."
The comment underscored the reality of Wisconsin politics after more than a decade of bruising political campaigns: There are very few swing voters left in the state, and both parties focused largely on turning out their own bases.