At a Saturday morning rally,
Representative Ben Ray Lujan of New Mexico, the head of the Democrats' campaign committee in the House,
drummed home the party's ethos of ignoring Mr. Trump while riding the backlash against him.
"We don't really have to even talk about this president —he's going to do all the talking about himself, for himself," Mr. Lujan said, addressing volunteers in Los Lunas,
where Democrats are making a push to pick up an open House seat.
"I want you to concentrate on families here in New Mexico."
But Senator Martin Henrich, appearing beside Mr. Lujan and Xochitl Torres Small, a water-use lawyer who is the Democratic nominee for Congress,
cast the election in dire terms familiar to anxious Democrats across the country.
"This is a battle for who we are as a nation,” said Mr. Heinrich, who is expected to win re-election easily on Tuesday.
That mind-set on the left has given Democrats an upper hand in campaign fund-raising.
Political spending in the election is expected to exceed 5 billion dollars, making it the most costly midterm contest in history,
according to a report by the Center for Responsive Politics.
The report found that Democratic candidates for the House had raised more money than their Republican competitors, by a margin of more than 300 million dollars.
But many Senate Democrats have also decisively outraised their contenders,
a sobering reminder to Republican officials about the rise of small-dollar and billionaire contributors on the left.
"If alarm bells aren't ringing across the Republican landscape as a result of the dollars Democrats have raised and the mechanism they raised them with,
then we don't deserve the majority,”
said Senator Cory Gardner of Colorado, who oversees the Senate Republican campaign arm.
Mr. Gardner warned that the Democrats' newfound fund-raising prowess could buffet his party even more in 2020,
when a less-inviting list of seats is up for election — including his own.
"We may be able to survive with this map in 2018, but we cannot survive that map in 2020,” he said.
It is the House, though, where Republicans face greater peril.
Most critical to determining control of the chamber are likely to be prosperous, culturally dynamic suburbs —
around cities like New York, Philadelphia, Detroit, Miami, Chicago and Los Angeles —
where Republicans are defending several dozen districts packed with voters in open revolt against Mr. Trump.