An incumbent U.S. senator faces Democratic primary challenges from a retired dentist in Keene and a Nashua man who describes himself as “an orthodox libertarian extremist.”

U.S. Sen. Jeanne Shaheen, a former governor, is on Tuesday’s primary ballot alongside Paul Krautmann and Tom Alciere.

In the Republican primary, Don Bolduc, Bryant “Corky” Messner, Gerard Beloin and Andy Martin are running. In addition, Justin O’Donnell of Nashua and Thomas Sharpe V of Salem have filed declarations of intent to run in the November general election as third-party candidates.

Here’s a look at the Democratic field:

Jeanne Shaheen

Jeanne Shaheen, 73, is a native of St. Charles, Mo., who has lived in New Hampshire since the 1970s. She served as New Hampshire’s governor from 1997 to 2003 and has been a U.S. senator since 2009, making her the first woman in U.S. history to have held both positions. In the Senate, she’s finishing her second, six-year term.

Prior to launching her political career, Shaheen earned a bachelor’s degree from Shippensburg University in Pennsylvania and a master’s from the University of Mississippi, according to her campaign website. She was also previously a small business owner. When she’s not in Washington, Shaheen lives in Madbury.

Her campaign did not follow through on a request for an interview.

During the COVID-19 pandemic, Shaheen has had a leading role in relief package negotiations, and has been a vocal proponent of more funding for states and municipalities, extended unemployment insurance and assistance for small businesses.

Shaheen’s campaign website says the senator has been in constant contact with representatives from the health care sector, first responders, business owners and others, and knows they still need help. “She is working to ensure they have the resources necessary to weather this crisis and rebuild a stronger economy,” the website says.

Beyond confronting the COVID crisis, Shaheen’s website says her priorities include providing services for veterans, decreasing the cost of health care, addressing climate change and reforming the U.S. immigration system, among other issues.

She has touted her ability to work with colleagues across the aisle, especially in negotiating the CARES Act but also in preserving funding for construction projects at the Portsmouth Naval Shipyard and boosting resources for opioid treatment.

Paul Krautmann

Paul Krautmann, 72, is a retired pediatric dentist who lives in Keene and moved to New Hampshire after completing his residency in 1979. The Higginsville, Mo., native has been an Elm City resident for 41 years.

He went to dental school at the University of Missouri-Kansas City, and completed his pediatric dental residency at the Medical College of Georgia. Once in Keene, Krautmann opened Paul J. Krautmann Pediatric Dentistry, which he ran from his Court Street home. In 2001, he began working at Concord Pediatric Dentistry and stayed there until his retirement at the end of 2013.

If elected to the Senate, Krautmann says his first priority would be reining in the nation’s military spending, and that he’d propose halving the Pentagon’s $740 billion budget.

“I don’t see any reason why we need that much money to fund the military,” he said. “I think it promotes war, and I’m anti-war.”

Krautmann has seen the cost of war first-hand. He served in the U.S. Army after being recruited during dental school, and deployed to Germany in 1972. He was in the U.S. Army Reserves until 2005, having achieved the rank of colonel.

In 2004, he deployed to Iraq for four months as a dental officer. He called the conflict a waste of time and manpower.

Krautmann is one of several participants in the anti-war protests most Saturdays on Keene’s Central Square.

He said U.S. forces have long overstayed their missions in Afghanistan and also in Iraq — the latter of which started on the premise that Saddam Hussein was hiding weapons of mass destruction that turned out to be nonexistent. One of the major reasons for his anti-war stance, Krautmann said, is that “most wars are based on lies.”

Krautmann also said he supports congressional term limits and said Capitol Hill needs some fresh faces. He said he takes issue with the tendency of government officials to later work as lobbyists, or in the case of military officials, for arms manufacturers.

“That’s a conflict of interest, because they use the fact that they know the people in Congress to unduly influence those people,” he said.

Krautmann supports establishing a universal health care system and examining police training protocols. And he expressed concern about how quickly New Hampshire has reopened after Gov. Chris Sununu issued a stay-at-home order in late March due to the COVID-19 pandemic.

He said his home state of Missouri opened up quickly as well and is now seeing a spike in infection rates. The jury is still out on whether that will happen in New Hampshire (where cases have declined significantly since May), he said, but he thinks the state should have been more cautious. He also took aim at President Donald Trump, who he said hasn’t managed the pandemic properly.

“I think we can get a better handle on it by testing and by following what the scientists are telling us,” he said, “which is to not gather, and wear masks.”

Tom Alciere

Also running is Tom Alciere of Nashua, who bills himself on his website as an “orthodox libertarian extremist.” He did not respond to a request for comment sent earlier this week via his Facebook page.

In 2001, shortly after being elected to the N.H. House, Alciere resigned amid public backlash to his comments in an interview with the Valley News of Lebanon, expressing support for the killing of police officers, according to a 2001 New York Times report.

Editor’s note: The Sentinel is previewing all contested primary races covering area communities. Tell us what you want the candidates to be talking about as they compete for your vote via our Voter Values survey at www.sentinelsource.com/vote.

Mia Summerson can be reached at 352-1234, extension 1435, or msummerson@keenesentinel.com. Follow her on Twitter

@MiaSummerson