Rep. Bill CassidyWilliam (Bill) Morgan CassidySenate GOP urges Trump administration to work closely with Congress on NAFTA GOP, Dem lawmakers come together for McCain documentary Graham working on new ObamaCare repeal bill MORE (R-La.) raised more than $1 million in the fourth quarter for his challenge to Sen. Mary LandrieuMary Loretta LandrieuLandrieu dynasty faces a pause in Louisiana Senate GOP rejects Trump’s call to go big on gun legislation Project Veritas at risk of losing fundraising license in New York, AG warns MORE (D-La.) and has nearly $4.2 million cash in the bank.

That’s an increase from his third quarter haul of just $700,000. And it's nearly on par, his campaign notes, with what Sen. David Vitter (R-La.) raised in the fourth quarter of 2009. And Cassidy has already banked almost as much as Landrieu’s last Republican challenger, state Treasurer John Kennedy, raised throughout his entire campaign in 2007-08.

Over the course of the past year, $225,000 of that overall haul came in the form of donations of $100 or less from Louisiana donors, his campaign said. 

Landrieu, one of Democrats’ most vulnerable incumbents, has been raising money for her reelection fight at a steady pace, drawing more than a million each quarter this year, and at the close of the last quarter had $5.8 million cash on hand. She has not yet reported her fourth quarter fundraising numbers.

While Cassidy is in a stronger financial position than previous Republicans that have challenged Landrieu, he’ll likely have to spend some of that money to stave off a challenge on his right flank from Rob Maness.

Maness, a former Air Force colonel, has launched a conservative bid for the seat and has already picked up the endorsements of a handful of prominent national conservative groups. State Rep. Paul Hollis is also running 

In Louisiana elections, all candidates, regardless of party, are on the primary ballot on November 4, and if Maness gains strength in the race, he could split the Republican vote and send the race to a runoff, where Republicans are less certain of their chances at defeating Landrieu.