Bloomberg reports: “An analysis by Bloomberg Government of historical data, election maps and public polling points to sweeping Democratic gains in the November election, when all 435 House seats and one-third of the Senate are on the ballot.” Adding to normal losses for the incumbent party in midterm elections is President Trump’s drag on the party. (“Trump’s approval rating at this stage of his presidency, 36 percent, is lower than any of his predecessors going back to Harry Truman, according to Gallup polling data.”)

When an environment is as inviting as 2018 seems to be for Democrats, it is comparatively easy to field strong candidates and raise money. “Through the end of September, 145 House Democratic challengers to 73 Republicans raised at least $100,000, according to the Campaign Finance Institute. At a similar point in 2015, 35 Democratic challengers to 25 incumbent Republicans raised more than $100,000.” The seats are there to be won with “23 districts that voted in 2016 for Clinton and for a House Republican. Seven are in California. There are another 12 Republican-held districts that Trump won but had voted to re-elect Democratic President Barack Obama in 2012. Seven of those are in New York and New Jersey.”

The biggest advantage Democrats have is Trump, who is busy alienating huge swaths of the electorate. “Democrats improved their showing in well-educated, historically Republican areas in the 2016 and 2017 elections, so some hard-fought races in the fall will be in the suburbs,” Bloomberg finds. “Among the House districts that may be in play are those of Representatives Rodney Frelinghuysen and Leonard Lance in New Jersey, John Culberson in the Houston area, Barbara Comstock in the Virginia suburbs near Washington, and Peter Roskam in the Chicago area.”

In the Senate, Republican retirements in Arizona and Tennessee, along with a particularly weak incumbent in Nevada (Dean Heller), give Democrats at least a mathematical chance to flip the Senate. With the upset win by Sen. Doug Jones (D-Ala.), Democrats need only a net pickup of two seats.

With numbers such as these, Democrats’ biggest problem — but not the only one — may be complacency. Their base, including occasional voters, must stay engaged; registration efforts especially in majority-minority districts must intensify.

Democrats face other challenges as well. Moderate Republicans will practically disown Trump and even avoid identifying themselves as Republicans. They will run on local issues. They will accuse Democrats of seeking gridlock or of diverting the country’s attention with an impeachment quest that is unlikely to remove him because of the high threshold for conviction in the Senate (a two-thirds vote).

Democrats’ task is threefold.

First, Democrats must make clear that the problem is a deadly combination of a hard-right congressional agenda and a chaotic president. The danger from the latter can be minimized by removing the GOP majorities, which encourage Trump’s unacceptable conduct and right-wing populism (actually a strange mix of populism and plutocrat-friendly economics.)

Follow Jennifer Rubin‘s opinionsFollowAdd

Second, Democrats must resist the urge to convert the election into a laundry list of grievances divided by gender and/or race. The horror of Trump, after all, is in part his divisiveness and use of antipathy toward “political correctness” to disguise out-and-out racism or misogyny. Democrats don’t want to play into that trap, but instead should be talking about themes that affect all Americans — health care, North Korea, infrastructure, Trump’s defiance of the rule of law. Sure, they should address the “dreamers” (nearly 90 percent of Americans want them to remain here), but one reason for defending their legalization is because they benefit all of us by serving in the military, working and paying taxes, getting involved in their communities, etc. Keeping them here is not only the humane thing to do, but also an example of enlightened self-interest.

Third, Democrats should not make the mistake of running down the economy. It’s the same economy, essentially, that President Barack Obama handed off to Trump. Rather, they need to make the case that the benefits of the economy need to be shared more widely and that investment in infrastructure, R&D and human capital are needed to sustain that economic recovery. If large chunks of the country are struggling, we cannot operate at full capacity.

Democrats can flip one or both houses, but if they sit on their laurels, focus on Trump to the exclusion of the Republican majorities, retreat into interest-group politics and sound hysterical about the economy, they will blow a historic opportunity.