U.S. President Donald Trump walks past Interior Secretary Ryan Zinke as he stands to address the 17th annual September 11 observance at the Flight 93 National Memorial near Shanksville, Pennsylvania, U.S., September 11, 2018.
U.S. President Donald Trump walks past Interior Secretary Ryan Zinke as he stands to address the 17th annual September 11 observance at the Flight 93 National Memorial near Shanksville, Pennsylvania, U.S., September 11, 2018. Reuters / Kevin Lamarque

A former member of Donald Trump's cabinet was attempting a return to the U.S. Congress in Montana and California Democrats concerned about crime may oust one of their own when voters headed to the polls in midterm primary elections in seven states on Tuesday.

Voters in South Dakota, New Jersey, Iowa, Mississippi and New Mexico were also casting ballots in nominating contests that will set the competitive field for Nov. 8's elections, which will determine control of Congress for the next two years.

With President Joe Biden slumping in the polls and soaring inflation souring voters' moods, Republicans are expected to win control of the House of Representatives and possibly the Senate, which would bring Biden's legislative agenda to a halt and give Republicans the power to launch distracting and possibly politically damaging investigations.

Just 41% of Americans approve of Biden's performance as president, near the lowest level of his presidency, according to a Reuters/Ipsos public opinion poll completed on Tuesday.

The poll also showed the Democratic Party and the Republican party were neck-and-neck in voter preferences ahead of the November congressional elections. Thirty-nine percent said they would vote for a Democrat compared to 37% picking a Republican. The difference was well within the poll's 4 percentage point credibility interval

More Americans also expressed confidence in Republicans' ability to deal with inflation, which has surged this year. Democrats had the advantage in voter preferences for responding to gun violence and for women's rights, issues that have become more prominent following a spate of mass shootings and expectations the U.S. Supreme Court could soon strike down a woman's constitutional right to abortion.

In Montana, Ryan Zinke, who served as interior secretary under Republican former President Trump, is running for a newly created House seat that the state gained thanks to population growth and the once-a-decade redistricting process.

Zinke, who served in Congress previously, faces four Republican challengers, some of whom claim that he is too liberal or lacks commitment to the state because his wife's residence is in California.

Zinke was accused in an inspector general report this year of using is position as head of the Interior Department to advance a development project in his hometown and lying to an ethics investigator. He has denied wrongdoing.

South Dakota's conservative Republican governor, Kristi Noem, faces a challenge by Steven Haugaard, a member of the South Dakota House of Representatives.

Noem has been mentioned as a possible vice presidential running-mate if former President Donald Trump seeks election again in 2024 or as a White House candidate in her own right if he does not.

The winners of each of those Republican primaries are favored to win in November.

CALIFORNIA SHAKEOUT

A pair of races in California will also illustrate liberal-leaning voters' frustrations with spikes in homicides and gun violence.

Polls show that San Francisco's progressive district attorney, Chesa Boudin, is likely to be pushed out of office in a recall vote. A replacement would be chosen by the city's mayor, London Breed, a Democrat who has criticized Boudin but has not taken a stance on the recall.

In Los Angeles, Rick Caruso, a billionaire developer and former Republican, is battling U.S. Representative Karen Bass and a host of other liberal candidates in the mayoral election.

Caruso, who has spent more than $30 million of his own money in the campaign, made crime the centerpiece of his candidacy in a city that saw homicides reach a 15-year high in 2021. That forced Bass, a longtime progressive champion in Congress, to move to the center and pledge to put more police on the streets. Caruso and Bass could be headed to a runoff, polls show.

NEW JERSEY, IOWA CHALLENGES

Republicans are also picking challengers to two embattled incumbent House Democrats: Representatives Tom Malinowski in New Jersey and Cindy Axne in Iowa.

Former state Senate Republican leader Tom Kean Jr., the son of popular two-time Governor Thomas Kean, leads a crowded Republican field to challenge Malinowski.

Malinowski, a two-term incumbent who entered Congress by flipping a Republican seat in 2018, won reelection by defeating Kean by 1.2 percentage points in 2020. Since then, his prospects have been weakened by redistricting and by a House ethics investigation after reports that he failed to disclose hundreds of thousands of dollars in stock trades.

"It was a nail-biter in 2020 and his district has become a little more favorable for Republicans. So it's going to be a significant challenge," said Benjamin Dworkin, director of the Rowan University Institute of Public Policy & Citizenship.

In Iowa, three Republicans are vying for the chance to challenge Axne: businesswoman Nicole Hasso, construction consultant Gary Leffler and former state Senator Zach Nunn.

Nunn, the only Republican contender who has held elective office, boasts a string of endorsements from high-profile party luminaries including Trump's former Secretary of State Mike Pompeo and several sitting House Republicans.