State Sen. Jim Tracy, a Republican challenging embattled GOP Rep. Scott DesJarlais in Tennessee’s 4th District, raised $150,000 in the fourth quarter, according to figures provided first to CQ Roll Call.

Tracy’s fourth-quarter haul brings his cash-on-hand total to $840,000 with about six months until the primary.

DesJarlais has yet to file his end-of-year fundraising report, which is due to the Federal Election Commission on Jan. 31. At the end of September, DesJarlais reported he had $170,000 in the bank.

DesJarlais ranks among the most vulnerable members in the House. A couple of years ago, damaging revelations surfaced from the congressman’s 2001 divorce proceedings that he encouraged a former wife and a former mistress to have multiple abortions.

Volunteer State Republican operatives now question his re-election prospects, especially in a primary. Tracy and DesJarlais are the two most prominent Republicans in the race, and the filing deadline is April 3.

No matter who wins the Aug. 7 Republican primary, this seat is not likely to switch party control. GOP presidential nominee Mitt Romney carried the district by a 32-point margin in 2012.

Tennessee’s 4th District is rated a Safe Republican contest by Rothenberg Political Report/Roll Call.