Republican congressional staffers remain hopeful that they'll enact significant legislation in 2017, but their Democratic counterparts are gaining confidence that they can block the GOP agenda, according to the June Capitol Insiders Survey of Hill aides.

Two-thirds of the Republican respondents expected it's at least somewhat likely they'll enact legislation to repeal and replace the 2010 health care law. But only one in five of the Democrats said the same.

The House passed a health care bill in May after Republican leaders worked out differences between conservative and moderate factions. But GOP senators have started over and they, too, face ideological chasms in their caucus.

Blame President Donald Trump, said Steve Elmendorf, a lobbyist who was once a top aide to Richard A. Gephardt when the Missourian was top Democrat in the House. Trump "is at 37 percent favorability in the polls and dropping and no one is scared of him on our side," Elmendorf said. "It drives people on our side to be unwilling to cooperate on anything."

The difference of opinion on the prospects for another Trump campaign promise, an overhaul of the tax code, was even more stark. On that question, nearly three in four Republicans who filled out the poll said a new law was at least somewhat likely, while only one in seven Democrats said the same.

The results are based on the Capitol Insiders Survey, CQ Roll Call's poll of congressional staffers. The poll was emailed to aides on May 31 and they had until June 16 to respond. Respondents comprised 76 Republicans, 73 Democrats and three independents.

The split was apparent on other key issues, too.

Among Republican respondents, 60 percent said they thought Congress and Trump would boost spending on infrastructure by $1 trillion over 10 years, but only 16 percent of Democrats thought so.

More than half of Republicans said they also expect Trump will deport at least 2 million undocumented immigrants who've committed crimes, while only 29 percent of Democrats believed he will. And 54 percent of Republicans said they'll eliminate funding for Planned Parenthood, the women's health care provider that offers abortion services, but only 34 percent of Democrats thought that will happen.

Tom Alexander, a public affairs strategist and onetime aide to two former Republican congresswomen, Tillie Fowler of Florida and Jennifer Dunn of Washington, said Democrats feel they can't trust the president enough to make deals. "Two words ... alternative facts," he said. "Without the assurance for Democrats that they're dealing in reality, there's little room for trust and compromise."

The differences of opinion between aides were also apparent on the Russia investigation, with nearly three-quarters of Democratic aides saying they believed that the Trump campaign had colluded with the Russian government to win the 2016 election. Only three of them said they believed Trump hadn't and the rest were undecided.

But Republican staffers weren't buying it. More than eight in 10 said they didn't believe the Trump campaign had worked with the Russians, while only 6 percent said they thought the campaign had.

The Republicans were split down the middle on whether the Russia investigation now underway at the FBI and separately at the Senate Intelligence Committee is a partisan witch hunt or an important inquiry affecting national security. Every Democrat said it was important.

Elmendorf said he thinks Republican worry is growing nonetheless. "I think privately there are a lot of Republicans who are concerned but they aren't ready to leave him yet," he said.

Asked if Trump would serve out his full term, a plurality of Democrats, 45 percent, said no. But 79 percent of Republican respondents said he would. Still, a plurality of them weren't thrilled about it. Nearly four in 10 Republican poll takers said he'd hurt the GOP in the 2018 midterms, while only a third said he'd help.

That "follows pretty closely with what all of us are thinking," Alexander said. "We just don't know yet. One thing for sure, though, 'unprecedented' has become a cliche in D.C. when trying to describe the actions of this White House. 2018 will be unprecedented."