Cao is unopposed for the Republican nomination, but that doesn't mean he hasn't been campaigning hard: of the $1.5 million he's raised, Cao has already spent over $1.2 million.
In the Democratic primary, four candidates have filed candidate papers. The most competitive contenders are both current Louisiana state senators: Cedric Richmond and Juan LaFonta. Richmond has the endorsement of the Democratic Congressional Campaign Committee, as well as a fundraising edge, with over $166,000 in the bank as of August 8 and over $550,000 in total receipts. LaFonta has taken in $328,941 this cycle, but reports only $13,590 at his disposal as of August 8. The winner will be closely watched in one of this year's few congressional races in which a GOP seat could go to the Democrats.