Trump could even help Republican candidates in some areas where he is popular and attracting new voters. In West Virginia, Bill Cole, the Republican candidate for governor, has embraced the billionaire because he "strikes a particular nerve." Trump won the state's primary on Tuesday with 77 percent of the vote.
Republicans have used sweeping gains in races for state legislative seats and governor's offices in 2010 and 2014 to enact measures cutting taxes, restricting abortion and collective-bargaining rights, and implementing new voting rules. They also have redrawn legislative districts to their advantage, hampering efforts by Democrats to groom candidates for higher office.
Twelve governorships are on the November ballot, with three Democrats and three Republicans seeking re-election, and six offices that will be open. About 80 percent of the 7,383 legislative seats in the U.S. are on the ballot, according to the National Conference of State Legislatures. Republicans control all but 30 of the 99 state House and Senate chambers, the most ever.
The Democratic Legislative Campaign Committee said it has targeted at least 13 chambers in 11 states now controlled by Republicans. In Colorado, Democrats are one seat short of a Senate majority. They are targeting three races in which they will tie Republican candidates to Trump's rhetoric through flyers, phone calls and door-to-door campaigning, said Rick Palacio, chairman of the state's Democratic Party.
Palacio said he expects the "Trump effect" to come into play especially in moderate suburban districts that historically have been bellwethers of voter sentiment nationwide.
Ryan Call, a former Colorado Republican Party chairman, said Trump jeopardizes the narrow Senate majority and could cost the party seats in the House as well. Democrats will try to "saddle" candidates with "all the policy positions, temperament, character and record" of Trump, he said.
"Many candidates have built constituencies and have a record quite in strong contrast to the kinds of positions Trump is taking," Call said. "Most are adopting the rhetoric of, 'I will support the Republican nominee for president.' They won't even mention his name."
In Nevada, Democrats are trying to reverse narrow Republicans majorities in the Senate and Assembly. Devon Reese, a Reno lawyer and Democrat running in the 15th Senate District, issued a press release May 5 criticizing potential opponents for supporting Trump. He said that publicity has helped him raise money.
"What I think voters do is they say, 'How could Senator X at the state level support this person who's such a fear monger, racist, hate-baiting kind of guy? That causes me to question their judgment,"' Reese said.
Reese will face the winner of the June 14 Republican primary between Heidi Gansert, a former chief of staff to Republican Gov. Brian Sandoval, and Eugene Hoover, owner of a courier company.
Although he backs Trump, Hoover said his victory in November if he's the nominee depends on Clinton being similarly unpalatable to Democrats.
"You've got to hope that those equal themselves out," he said. "Obviously, if they don't, you're going to be on the losing end."
Gansert didn't return telephone messages seeking comment on Trump and her race, and told the Reno Journal-Gazette she isn't focused on the presidential race.
The Michigan Democratic Party also will help candidates link Trump to Republicans running for the statehouse, Chairman Brandon Dillon said.
"We're going to make sure that voters understand in those districts, those down-ballot districts, that when you're voting for Republican A in District B, that you're essentially also casting a vote for the agenda of Donald Trump," he said.
The Democratic Governors Association has a "Trump Tracker" website that lists where Republican candidates stand on Trump. The group thinks his presence could be a factor in states including North Carolina, New Hampshire and Vermont, said spokesman Jared Leopold. The Republican candidate in Vermont, Lt. Gov. Phil Scott, has said he can't vote for Trump or Clinton.
"Governor's races tend to be more distinct and less partisan than federal races, but it's a tough uphill climb for Republicans who are running into the wind of a news cycle that's going to be dominated by Donald Trump," Leopold said.
Democrats are "desperate to talk about anything other than their candidates" and the "extreme negatives" of President Obama and Clinton in the states they are defending, said Jon Thompson, a spokesman for the Republican Governors Association.
Any drop-off in Republicans voting for president will affect other candidates, said Jennifer Duffy, an analyst at the nonpartisan Cook Political Report in Washington.
"It's going to be a constant answering to questions about Trump, and I think that goes all the way down the ballot," Duffy said.