Republicans, fresh off a victory on tax reform, say they are eager to pursue an aggressive 2018 agenda that includes immigration reform, a welfare-to-work bill, and even a costly infrastructure measure.

But the GOP agenda is about to hit the typical hurdles thrown in front of lawmakers who try to pass major legislation in a pivotal election year.

“Inevitably, the looming election cuts into legislative time and makes many members cautious about passing big-ticket items,” said University of Virginia political science professor Larry Sabato.

Just ask former House Majority Leader Steny Hoyer, D-Md., who ran the chamber schedule from 2006-2010.

House Democrats passed Obamacare in March 2010, but the agenda slowed in the remaining months leading up to the November elections, which ultimately wiped out the Democrats and returned the majority to the GOP.

“It’s tough,” Hoyer, who is now the minority whip, told the Washington Examiner. “But if I were the Republicans, I’d try to get some things done in a bipartisan way because I think that would be helpful to them.”

Some analysts predict big gains for Democrats in November, even a takeover in the House, where Republicans have held the majority since 2010 and now enjoy a 21-seat advantage.

Midterm elections can be disastrous for the party of the president, and President Trump is particularly unpopular, according to polls.

[Democrats hope 2018 is the year they take back power from Trump]

The public’s view of Trump and the GOP could make lawmakers reluctant to tackle anything big, particularly welfare reform.

“It's very likely the GOP will lose House seats, and possibly a lot of them,” Sabato said. “That reinforces their innate caution.”

Trump isn’t backing down on an aggressive agenda just because it’s an election year. He’s calling on Congress to next tackle a massive infrastructure bill, which would force lawmakers to pass something that could cost more than $1 trillion.

But Republicans acknowledge they would be challenged to come up with an expensive infrastructure bill that would also require a way to pay for it without raising taxes.

“It’s more difficult,” Rep. Mike Simpson, R-Idaho, said.

In past election years, legislation slowed pretty quickly in Congress.

Former House Speaker Dennis Hastert used to proclaim it impossible to move significant measures past March when lawmakers faced voters the following November.

Republican lawmakers acknowledged they need to move quickly to get must-pass bills across the finish line this year.

Among the top-priority legislation is a bill to legalize young people who came to the U.S. illegally as children.

A federal program allowing children of illegal immigrants to remain in the U.S. expires in March and Trump has called on Congress to pass legislation to address the matter.

Lawmakers are eager to work out a deal with Democrats that would legalize those in that situation in exchange for border security measures that include money for a southern wall.

A bipartisan working group is working on an accord. Sen. Jeff Flake, R-Ariz., said he believes legislation will be ready for a vote in January and Republican leaders said they think a deal is possible that includes new border security in exchange for legalizing so-called Dreamers.

“We are not quite there yet,” Homeland Security Committee Chairman Michael McCaul, R-Texas, told the Washington Examiner.

The election year will make passage of a deal difficult, McCaul acknowledged, but it can happen “if we do it early enough.”

Congress must also pass legislation to increase the nation’s borrowing limit, which may be reached as early as March.

And lawmakers will have to pass spending legislation to fund the government for the remainder of fiscal 2018, plus come up with a new spending measure for 2019 by the end of September.

Outside of government spending, Republicans say they will try to tackle legislation reforming the nation’s welfare programs.

House Speaker Paul Ryan, R-Wis., promised conservatives a vote on legislation aimed at curbing the growth of welfare spending and tying the benefit to work.

Some of those reforms will come up in the 2018 farm bill, which authorizes food stamp spending under the Supplemental Nutrition Assistance Program, otherwise known as SNAP.

House Agriculture Committee Chairman Mike Conaway, R-Texas, said the election won’t stop him from incorporating work requirements for food stamp eligibility.

“We are going to try to make the SNAP part of the bill good public policy and nonpartisan as well,” Conaway said.