A candidate hoping to run for governor in the US state of Iowa has lost a closely watched primary contest, despite getting the backing of Donald Trump.

Randy Feenstra, who was seen by many as a frontrunner, conceded the race on Tuesday, having received a last-minute presidential endorsement ahead of the vote.

The three-term Iowa congressman, who was running for his party's nomination for November's governor contest, had also been a reliable Trump supporter.

But for his part, the winner, farmer and businessman Zach Lahn, campaigned on a decidedly Trumpian platform – with slogans like "Make Iowa Healthy Again" and "Iowa first".

He campaigned on limiting foreign and out-of-state ownership of Iowa land and railed against "global elites".

Lahn also had the backing of Turning Point USA, the conservative group founded by the late Charlie Kirk, and grassroots conservatives in the state who viewed Feenstra as too much a part of the Washington establishment.

Trump has been out of the public eye the past six days, other than prerecorded interviews with friendly media and his postings on Truth Social, which included an assertion that negotiations with Iran over the war "have been going on continuously".

While the talks may be ongoing, they don't seem to be making much progress. It's been a rough week for Trump domestically as well - his administration has abandoned plans to create a $1.8bn (£1.3bn) "anti-weaponisation" fund. The fund had been designed to compensate individuals who claimed to be targets of political investigation by previous presidential administrations.

And Tuesday night marked a hit to his golden track record of political endorsements.

Over the past few weeks, it has appeared like a Trump endorsement was a guaranteed ticket to success.

Congressman Thomas Massie in Kentucky and Senator Bill Cassidy were both unseated by Trump-backed challengers. And Texas Attorney General Ken Paxton won his state's Republican Senate nomination contest over incumbent John Cornyn - although it appeared increasingly likely that Paxton was going to defeat his opponent with without Trump's help.

As for the Feenstra result - that may prove to be a case of the president's political instincts being off in a state that, while voting for him in three straight elections, appears to be a souring a bit.

Trump's wide-ranging programme of trade tariffs – and the Chinese response to them – have hit Iowa's farmers hard. And then came the US-Israeli war with Iran, packing a double punch with its higher fuel and fertiliser costs.

According to a recent YouGov/Economist poll, Trump has a net approval rating of -20% in Iowa.

This unease has given Democrats hope of flipping the governorship, where Lahn will now face off in November against Democratic State Auditor Rob Sand.

Democrats are also targeting the Senate seat being vacated by Republican Joni Ernst. Projected results show that Paralympian Josh Turek - a centrist who had the backing of national Democrats - won his party's primary and will go on to face Republican candidate Ashley Hinson.

Several election analysis groups have moved both races to a toss-up or leans Republican.

So, while Texas gets a lot of national attention, the key to Democratic success in November may lie amidst the cornfields of Iowa - which was once generally blue but has voted red in recent years.

That all makes it worth keeping a close eye on the Hawkeye State.