Major clashes on policy often play a significant role in competitive Senate primaries, usually with the incumbent being accused of ideological apostasy on key issues. However, incumbent Sen. Ed Markey has strong credentials with the progressive base of the Massachusetts Democratic party, and he has taken a leading role in promoting major progressive initiatives, such as the Green New Deal. Rep. Joe Kennedy has considerable overlap with Markey on many policy issues. Tuesday’s debate highlighted the way that the Markey-Kennedy race is a battle less over policy and more over brand and political style. But those stylistic elements may reveal deeper trends in American politics.

Neither candidate spent much time outlining sharp policy contrasts with his opponent. Indeed, Kennedy opened with a declaration that Markey had been a “good senator.” There was even a moment of mutual discomfort on policy when both Markey and Kennedy struggled to give a direct answer to whether they wanted to phase out private health insurance. The reticence on this issue suggests some of the possible landmines that could await a progressive push for Medicare for All: Both presidential and Senate contenders have stumbled on the issue of private health insurance under this proposal.

Foreign policy was, though, one issue where the candidates went head to head — sort of. They differed a bit on troop draw-downs in Afghanistan, with Kennedy pushing for a more expeditious withdrawal and Markey supporting a more gradual approach. Kennedy attacked Markey’s votes on Iraq and a possible U.S. intervention in the Syrian civil war.

In some respects, Kennedy and Markey seemed less to be running against each other and more against President Donald Trump. Criticisms of the president dotted the debate. Markey, for instance, accused Trump of “making American hate again.”

There were some stylistic differences. Markey presented himself as a veteran of legislative wrangling, while Kennedy claimed the mantle of a youthful, progressive pugilist. Throughout the debate, Kennedy appealed again and again to the urgency of the moment as a reason for his candidacy: “For this election, this time around, so much of what we care about — everything that we care about — is on the line.”

In this appeal to urgency, Kennedy tapped into broader cultural currents. Since 2016, American politics has grown more confrontational, and factional polarization has heightened. The presence of Donald Trump in the White House is a continued source of angst for many Democratic voters. Kennedy is trying to use this frustration as a springboard for his Senate bid. He continually stressed the importance of fighting hard against the president and Republicans. As he put it rather starkly in his closing remarks, “this is all about power.”

On those structural questions of the exercise of power, Kennedy reflects some of the temperament of the times. Kennedy’s campaign has been marked by calls to reverse some of the institutional incentives for compromise (such as the filibuster and the Electoral College). The filibuster in particular has long been a device for encouraging bipartisan cooperation in the United States Senate, but those institutions that encourage compromise grow less fashionable in a polarized time. Now, both Trump and Kennedy support eliminating the filibuster. (Maybe bipartisanship isn’t dead, after all.) Markey has traditionally been more supportive of the filibuster, but he has started to criticize it more under the pressure of the primary campaign.

No-holds-barred politics has perhaps always been appealing, though it has acquired a particular shine in recent years. If everything seems to be on the line, no quarter can be spared. It might be worth remembering, though, that most of the men featured in "Profiles in Courage" were those who resisted the passions of their times and saw that compromise could sometimes serve the interest of prudence.

Fred Bauer is a writer from New England whose work has been featured in National Review, The Weekly Standard and other publications. You can follow him on Twitter @fredbauerblog.