WASHINGTON -- Politics is regularly described in terms of "left" vs. "right." But other binaries can be more relevant. "Forward" vs. "backward" often define a choice facing an electorate better than the standard ideological categories. And the most powerful face-off of all may be "reform" vs. "corruption."

Much commentary on the 2018 midterm campaign has focused on a drift or a lurch left in the Democratic Party, the measurement of the portside tilt varying from analyst to analyst. In fact, more moderate progressives have done very well in the primaries so far, but Democrats are certainly less enamored of centrism than they were in the 1990s.

What's missed in this sort of analysis is that many, maybe most, of us don't think in simple left-right terms, and countless issues are not cleanly identified this way. The same is true of elections. When the returns are tallied in November, the results may be better explained by the reform/corruption dynamic than any other.

New York magazine's Jonathan Chait was one of the first journalists to suggest how important corruption could be in this year's campaign. Writing in April, Chait argued that it "should take very little work" for Democratic candidates "to stitch all the administration's misdeeds together into a tale of unchecked greed."

The advantages of the corruption issue are (1) "corrupt" really is the right word to describe the Trump administration; (2) a concern over corruption transcends philosophical dispositions; and (3) the failure to "drain the swamp" is one of President Trump's most obvious broken promises. Instead, Trump has turned the swamp into an immense toxic-waste dump. The stench emanates from Cabinet officials driven from office by egregious behavior and from Trump's own violations of long-standing norms limiting business dealings by presidents and their families.

But the corruption issue goes beyond meat-and-potatoes sleaze. Our democracy itself is in danger from the overpowering influence of money on our politics, unchecked foreign intervention in our elections and an increasing willingness of Republicans to bias the system in their favor through gerrymandering and restrictions on access to the ballot.

And Trumpian corruption has shown that we counted too much on the decency of public officials. Alas, we now know that basic expectations -- from the release of tax returns by presidential candidates to the avoidance of blatant conflicts of interest -- need to be codified. Scandals are like that: They teach us where existing laws fall short.

A program to renew self-rule is coming to a congressional campaign near you. In late June, Rep. John Sarbanes, D-Md., introduced a resolution outlining a broad agenda that has been co-sponsored by 163 House Democrats. It's a promissory note to the electorate outlining areas where the party is working on legislation it pledges to enact should it win a majority.

They would start by restoring the effectiveness of the Voting Rights Act, gutted by the Supreme Court in 2013; providing for nationwide automatic voter registration; ending purges that illegitimately disenfranchise many citizens; and outlawing gerrymandering by requiring states to establish cross-party commissions to draw district lines.

A high priority would involve creating a campaign-finance regimen aimed at encouraging congressional candidates to rely on small contributions while also restoring the public-finance system for presidential campaigns. Sarbanes and Rep. David Price, D-N.C. -- two of the leading foes of the tyranny of big money in politics -- have joined forces to harmonize proposals each has offered over the years.

Responding directly to recent abuses, the package would codify ethics expectations of public officials -- including presidents. To fight foreign meddling, it calls for "real-time transparency of political advertisements on all advertising platforms," an idea championed by Sen. Amy Klobuchar, D-Minn.

Sarbanes said in an interview that the goal is not simply to have a campaign theme that appeals to conservatives, independents and progressives alike, but also to commit his party to specific actions. "This is not a message you wear," he said. "This is a message you own."

Even if Democrats won the House, enacting their program into law would likely involve a struggle beyond the 2020 elections. But the transformative eras of the past -- the Progressive, New Deal, civil rights and post-Watergate periods -- were all the product of a long gestation and continuous organizing.

They were also sparked by a disgust with the status quo. "There are moments in history," said Fred Wertheimer, the president of Democracy 21 and veteran clean-government advocate, "when scandals create the possibility of fundamental reform." This would be a happily ironic coda to the Trump presidency.

(c) 2018, Washington Post Writers Group