Ben Sasse is not OK with Donald Trump’s tweets. On June 29, the president began yet another day by barfing out insults on Twitter, this time regarding MSNBC host Mika Brzezinski’s face. Sasse was one of the first Republicans to respond. “Please just stop,” wroteNebraska’s 45-year-old junior senator. “This isn’t normal and it’s beneath the dignity of your office.”

Dignity is one of Ben Sasse’s things. He’s also into duty, thoughtfulness, empiricism, and respect for democratic traditions—and while most politicians would probably claim to support those ideals, Sasse sets himself apart by frequently challenging his party on their behalf. The Morning Joe incident was not nearly the first time Sasse has criticized Trump without rationalizing or minimizing his behavior the way so many in the GOP do; during the 2016 presidential campaign, Sasse refused to endorse the real estate heir even as almost all of his Republican peers in elected office folded. (He called for an independent candidate to run against Trump and Clinton in a widely discussed Facebook post but reportedly rebuffed suggestions by Mitt Romney and Bill Kristol that he become that candidate himself.) Just this Sunday, Sasse called Trump’s claim to be working on a cybersecurity commission with Vladimir Putin “bizarre” and noted (correctly) that it “should obviously not happen.”

But at the same time, Sasse’s Senate votes have so far aligned with Trump’s wishes 95 percent of the time, the same level of support that Trump has gotten from right-wing ideologues like Ted Cruz and party loyalists like Chuck Grassley. Sasse voted to confirm ill-informed Cabinet appointees like Ben Carson and Betsy DeVos; he’s voted to steamroll the judicial filibuster and stayed silent about the secretive way the Republican health care bill was written and presented to the public. During a June 25 appearance at a conservative activist conference, as other senators in his own party were criticizing the bill and the process by which it had been constructed, Sasse asked whether his remarks would be on the record before announcing that he would not have any comments at all. It was only after the proposal had almost completely stalled that Sasse proposed an alternative.

This, in a nutshell, is the central problem of Ben Sasse. He is a performatively deep thinker, an advocate of public decency who makes a case for good-faith discourse that is both eloquent and, in the FAKE NEWS!!!!!!1! era, timely. He states that case convincingly in his new book about raising hard-working and civic-minded children, The Vanishing American Adult. “Living in a republic demands a great deal of us,” he writes in a sort of mission statement for his public persona. “Among the responsibilities of each citizen in a participatory democracy is keeping ourselves sufficiently informed so that we can participate effectively, argue our positions honorably, and hopefully, forge sufficient consensus to understand each other and then to govern.” But so far, Sasse’s practical participation in our democracy—he was elected to the Senate in 2014—has mostly advanced the interests of an increasingly authoritarian, unreasonable Republican Party. In his first remarks on the Senate floor, he argued that the body should “strengthen and clarify meaningful contests of ideas.” Four months later, he wouldn’t even give Obama Supreme Court nominee Merrick Garland a perfunctory meeting. And he certainly didn’t advocate giving Garland a hearing and a floor vote, as one would imagine he should have given his expressed desire for the Senate to become a lively forum for dramatic, legitimate debate rather than pre-written sound bites and predictable party-line votes. ...