Sen. Al FrankenAlan (Al) Stuart FrankenShould the Rob Porter outcome set the standard? Grassley, Dems step up battle over judicial nominees Sen. Gillibrand, eyeing 2020 bid, rankles some Democrats MORE (D-Minn.) on Friday asked Democrats to provide more donations to his colleagues, warning that several of his fellow Democratic senators could end up reprising the months-long recount that kept him from taking his Senate seat.

Franken wrote in a fundraising e-mail for the Democratic Senatorial Campaign Committee (DSCC) that some of his colleagues — like Sens. Barbara BoxerBarbara Levy BoxerKamala Harris endorses Gavin Newsom for California governor Dems face hard choice for State of the Union response Billionaire Steyer to push for Dem House push MORE (Calif.), Russ Feingold (Wis.) or Patty MurrayPatricia (Patty) Lynn Murray30 million people will experience eating disorders — the CDC needs to help Mulvaney remarks on Trump budget plan spark confusion Overnight Finance: Mulvaney sparks confusion with budget remarks | Trump spars with lawmakers on tariffs | Treasury looks to kill 300 tax regs | Intel chief's warning on debt MORE (Wash.) — could end up in races that are determined by just a few votes.

"Barbara Boxer, Russ Feingold, Patty Murray: Any of these great Democrats could end up in a race as close as mine," Franken wrote. "Any of these 15 races could swing the Senate majority. And that means even a small contribution could make a very big difference."

Franken won the 2008 Minnesota race against incumbent Sen. Norm Coleman (R) by only 312 votes. The final tally was approved only after an extensive, drawn-out recount that was litigated in court for months. It took Franken until July 9, 2009, to be sworn in.

The senator's e-mail for the DSCC underscores just how close some of the Senate races facing Democrats might be. While Boxer and Murray have slight leads in the polls, their races could come down to the wire. Feingold is perceived as trailing slightly in his race, though his incumbent status could also make his contest against Republican Ron JohnsonRonald (Ron) Harold JohnsonTrump spars with GOP lawmakers on steel tariffs Overnight Regulation: Trump unveils budget | Sharp cuts proposed for EPA, HHS | Trump aims to speed environmental reviews | Officials propose repealing most of methane leak rule Trump budget seeks savings through ObamaCare repeal MORE a nail-biter.

"We can win this thing. We can stop the Tea Party," Franken said. "But to do it, we have to fight for every single one of these 15 razor-tight races. And that means we need you to step up to the plate right now."