Missourians who watch television could be excused for believing there actually is an airline called Air Claire, or that Missouri Attorney General Josh Hawley really is fighting for mandatory insurance coverage of pre-existing conditions. The massive ad buys for the candidates in Missouri’s U.S. Senate race reflect how desperate both major parties are to win this potentially balance-tipping seat.

The measure of a campaign’s desperation is its willingness to bend the truth, even to the breaking point, just to garner a few extra votes. Integrity matters. Values matter. Civility matters.

Incumbent Democratic Sen. Claire McCaskill has a long record of service in elective office. Her bipartisan voting record reflects the moderate political tendencies of Missouri voters. She is tough, well-versed on a broad array of domestic and international issues, and proudly stands her ground in the male-dominated world of Capitol Hill politics.

This newspaper endorses McCaskill, 65, in the Nov. 6 election for U.S. Senate.

We had expected a harder choice, but GOP candidate Josh Hawley, the state attorney general, has made it easier by undermining his own competitiveness with political miscalculations and blunders. He is running his campaign from the gutter and is employing a shameful array of misleading tactics to make Missourians believe he’s someone he clearly is not. GOP dark-money groups are flooding the airwaves with desperate support ads designed to distort McCaskill’s record and distract voters from Hawley’s lack of a record.

Hawley, with less than two years in office, is too inexperienced, veers dangerously toward political extremism, and is about as sincere as a used-car salesman. He hasn’t come close to earning the office he seeks, much less the one he currently occupies in Jefferson City.

McCaskill offers a voting record that reflects the centrist, bipartisan tenor we’d like more Missouri candidates to adopt. This state is neither solid red nor solid blue. Its voters are split down the middle, and Missouri’s congressional representation should reflect that.

The political website Fivethirtyeight.com, which tracks voting patterns in Congress, says that McCaskill voted 44.9 percent of the time in line with President Donald Trump’s agenda since he took office. Our biggest problem with Trump is his divisiveness, crass language and lax ethical standards. McCaskill’s voting record reflects her ability to sift through Trump’s personality problems and evaluate the merits of administration bills and nominations.

That’s what independent thinkers do. That’s what true leaders do.

Hawley claims to support solid Midwestern family values. He calls himself a dedicated Trump supporter, ignoring the president’s racism, sexism and sympathetic comments toward white supremacists. When Trump stands in support of world dictators and egregious human-rights abusers, Hawley stands with him.

We repeatedly invited Hawley for an interview, but his campaign wouldn’t commit. We’ve spoken with him in the past and found him to be a good man whose conservative values and Yale Law School education appeared not to harden him to the economic and health care struggles challenging millions of Missourians. Though he was slow to venture forth with legal challenges to the multiple scandals engulfing former Gov. Eric Greitens, Hawley did ultimately show some courage in helping pressure the state’s top Republican to resign.

But that version of Hawley is nowhere to be seen today on the campaign trail. He’s been replaced by a robotic figure who looks sincerely into the camera lens, then deliberately distorts the truth.

Hawley stoops to using the image of his young son, who suffers from a chronic disease, to assert his support for mandatory insurance coverage of pre-existing conditions. Yet Hawley is one of 20 GOP attorneys general to have joined a federal lawsuit to overturn the Affordable Care Act — Obamacare — including the act’s highly popular mandate for insurance coverage of pre-existing conditions. Hawley would deprive millions of Americans of medical coverage just to score political points against Obamacare. His replacement proposal is laughable — and unworkable.

Hawley also mocks McCaskill as an elitist who flies around Missouri on a private plane. Yet Hawley grovels before the ultimate elitist in the White House who gained fame by jetting around the world on his private passenger plane and who now spends hundreds of millions in taxpayer dollars just to spend weekends at his private resorts.

True leaders don’t allow their core values to be distorted with double-standard hypocrisy. Hawley comes across as a ladder-climbing phony, as Charlie Brennan and conservative radio talk show host Mark Reardon observed last month on KMOX.

McCaskill doesn’t sweet-talk anybody with false sincerity or sugarcoat the challenges of representing such a politically diverse state. She recognizes the political reality that, sometimes, a politician has to stand against her own party if she truly wants to represent her constituents and her values. “Compromise matters,” she told us. “Bipartisanship matters.”

No one can be sure what Hawley stands for. He needs to finish the job he was elected to do as attorney general, and voters should let Claire McCaskill continue doing the job she was elected to do.

Also running are Libertarian Japheth Campbell, Jo Crain of the Green Party and Independent Craig O’Dear.