As was the case two years ago, Democratic candidates are at a financial disadvantage in almost all of the Iowa Senate districts both parties are targeting.

The disparity adds another challenge to a party already facing a difficult path to gaining ground in the upper chamber. Republicans currently hold 29 of the 50 Senate seats and are guaranteed to pick up the district independent Senator David Johnson is vacating.

Five weeks before the general election, the Republican Party of Iowa has begun airing television commercials to promote Senate Majority Leader Jack Whitver and State Senator Julian Garrett.

The advertising suggests that Republican internal polling shows Democrats Amber Gustafson and Vicky Brenner within striking distance in Senate districts 19 and 13, respectively. Democratic internal polling presumably shows competitive races too, since former President Barack Obama included Gustafson and Brenner on his list of Iowa endorsements this week. Only five state legislative candidates made the cut.

Republicans are all but guaranteed to maintain control of the Iowa Senate after November and could expand their majority, now at 29 out of 50 seats. However, Democrats have a chance to pick up a few districts as they work toward winning back the chamber in 2020.

More Iowa women are running for office in 2018 than ever before, which could lead to record numbers of female state representatives and senators next year.

However, in other meaningful ways, Iowa’s legislature could become less diverse after the November election.