Iowa went Trump in 2016, which saw the Democrats blown out of the water that year. Iowa Democrats are seeking to un-fracture their party which saw supporters defect from establishment candidate Hillary to outsider Progressive Senator Bernie Sanders in the 2016 primary caucuses. In fact, in 2016, Republicans stole the state Senate, making the state a trifecta of GOP control beginning in the 2017 legislative session.

Governor

Incumbent Gov. Kim Reynolds is alone representing the Republicans and she will face off with  Democrat Fed Hubbell a former business owner. They have widely divergent philosophies on health care, explained here, by Vox.

"Expect health care and Trump’s approval rating to come into play in this race. Reynolds’s signature achievement is probably moving Iowa’s 600,000 Medicaid enrollees into managed care, a privatized version of the program where private health plans administer Medicaid’s benefits. Hubbell wants to reverse that privatization..."

Iowa’s third US Congressional District: Again, more healthcare.

The Republican incumbent, Rep. David Young, who voted to repeal Obama Care will run against Cindy Axne, a former small-business owner in November. This race is all about progressive visions of healthcare and moderate platforms.

Iowa’s first US Congressional District

In the eastern part of the state, it was a four-way race for the Democratic spot in the November general elections with state legislator Abby Finkenauer, clinching the win.  Republican Rep. Rod Blum is the Republican incumbent.   This race makes Blum vulnerable to the Democrats; his seat is widely seen as the most vulnerable seat in the US House of Representatives. If Finkenauer wins, she will be the youngest women elected to Congress in US history.

Battle Ground Primary

This race is considered a 2018 Battle Ground Primary for the House of Representatives according to the following criteria laid out by Ballotpedia.

• Whether or not the seat is open (retiring or resigning incumbent)
• Notable endorsements of multiple candidates
• Significant fundraising from multiple candidates
• Number of candidates
• Incumbent's years in office (if seeking re-election)
• Whether or not the district's general election is expected to be a battleground

Other Battleground Primaries are listed here.