Vulnerable Sen. Johnson raises $1.6M
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Sen. Ron JohnsonRonald (Ron) Harold JohnsonGOP senators introduce Trump's plan to claw back billion in spending House GOP sets three FBI interviews in Clinton probe Overnight Health Care — Sponsored by PCMA — House passes 'right to try' drug bill | Trump moves to restrict abortion referrals MORE (Wis.), one of the most endangered GOP Senate incumbents, raised $1.6 million in the final fundraising quarter of 2015, bringing his 2015 fundraising total to $6.3 million.

The GOP senator was about $1 million shy of Democratic Senate candidate Russ Feingold, who raised nearly $2.7 million in the fourth quarter. The former Wisconsin senator’s latest haul brings his 2015 fundraising total to more than $7.4 million.

Despite outpacing Johnson in fundraising, Feingold only has a slight cash advantage with $4.8 million cash on hand, compared to Johnson’s $4.4 million cash on hand.

Johnson brought in a fair haul compared to other Republican incumbents running in top-tier races. Johnson’s campaign also recently announced that it hired a Wisconsin finance director and digital director.

“Ron Johnson continues to earn the support of Wisconsinites because he is a citizen legislator who fights for Wisconsin taxpayers,” said Johnson campaign spokesman Brian Reisinger. “The people of Wisconsin fired Senator Feingold in 2010 because he was taking our country in the wrong direction, and we’re confident his broken promises and dangerously weak national security record will convince them to do so again.”

Feingold is challenging the GOP senator to a rematch after Johnson edged him out by nearly 5 points in the 2010 election.

Late 2015 polling in Wisconsin showed Feingold with a double-digit lead over Johnson. A new Marquette Law School survey released Thursday found Feingold holding a 13-point lead over Johnson.

Senate Democrats and Republicans are in a heated battle over the majority this cycle.

Democrats need to net five Senate seats in 2016 to regain a majority in the upper chamber — unless they retain the White House. Then a net gain of four seats would give them the majority, with the vice president breaking a 50-50 tie.

Democrats are considered to have an advantage in that they are only defending 10 Senate seats, while the GOP is defending 24 seats.