Now that they have one of their own in the White House, Republicans in Congress have ambitious plans: overhauling the country's financial regulation, upending health policy, rewriting the new tax code and rebuilding the country's infrastructure.

With so much work to do, even a veteran lawmaker steeped in the details of public policy could struggle to keep it all straight. For the heavy lifting of writing amendments and making bills, legislators have traditionally turned to their aides, who spend their work days burrowing into niche policy areas.

But at a time when lawmakers are badly in need of advice from their staff, the typical lawmaker will have fewer of them to turn to. The average number of aides supporting a rank-and-file House member has been in decline for several years because of budget cuts.

Meanwhile, Congress's independent research bodies — agencies once filled with lawyers, engineers, physicists and economists on call to answer technical questions about complicated bills — have long been short-staffed as lawmakers have looked for ways to save money.

The shift, according to interviews with current and former legislators, their aides and political scientists, has left lawmakers short on expertise, preparation and know-how. They have been forced to rely on lobbyists and party leaders to guide them through the legislative process, and many rank-and-file members are effectively sidelined.

A lack of emphasis on knowledgeable staff is “one of the weaknesses of the Congress in the modern era,” said former congressman Jim Leach (R-Iowa.). “The more complicated society has become, the more complicated government becomes, and the more important it is to have professional expertise.”

“Almost everybody that you will talk to on the Hill will say something like, ‘We don't have the expertise that we need,’ ” said Lee Drutman, a political scientist at the New America Foundation in Washington.

In the House, the average rank-and-file member has lost at least two full-time aides in just the past six years, according to the Brookings Institution. Pay has declined for employees in almost every category, the nonpartisan Congressional Research Service has found.

The only exception are chiefs of staff, whose salaries have increased by a meager 4.3 percent since 2001 after adjusting for inflation, according to the CRS. Experienced staff often move on to better-paid jobs elsewhere.

“Right now, I worry — if you try to do a big bill — that there aren’t that many people who have been through the process and understand how it works,” said a senior Democratic aide to a Senate committee. Congressional aides interviewed for this article were granted anonymity to speak candidly about their experiences working on the Hill.

“These are intelligent kids. I have full faith in their capability to go on and be successful in life, but they’ve only served on the Hill for three years,” a Republican chief of staff in the House said. “It’s just not worth it anymore financially.”

The change is subtle but could have serious consequences for Republicans in Congress as they work through a daunting legislative agenda.

Already, Republicans in the House have sent bills restructuring the banking industry and undoing the Affordable Care Act, also known as Obamacare, to the Senate. These bills address two of the most important and complex sectors of the U.S. economy, and Congress is still far from sending anything to President Trump's desk for his signature.

While they're at it, Republicans also hope to redo the tax code and rebuild the country's infrastructure.

Besides the legislation itself, reduced staffs have other new demands on their time, sources in Congress say. Campaign finance is less regulated, forcing some members to call more donors to ask for money. Increasing anti-incumbent sentiment could make staving off challengers for their seats more difficult. And lawmakers are busy with media platforms that did not exist until recently, talking to cable-news cameras and their followers on Twitter.

“It just feels more frenetic,” the Republican chief of staff said.

Resources for rank-and-file members have been in decline for decades, while congressional leaders have been augmenting their power and influence.

The most recent changes in the House were instituted under then-House Speaker John A. Boehner (R-Ohio) to constrain Congress's budget after the financial crisis. Already, though, fewer aides were working on the Hill.

The most drastic shift occurred under then-House Speaker Newt Gingrich (R-Ga.). Gingrich's retooling forced out over 2,000 experts serving on the staffs of congressional committees and joint agencies such as the Congressional Budget Office. The Office of Technology Assessment — a bureau of about 140 scientists and other experts that provided analysis on health care, energy, weapons, infrastructure and more — was shuttered entirely.

Reducing congressional staff was one of the pledges Republicans made in the “Contract with America,” their winning platform in the midterm election of 1994. They argued Congress had become wasteful and unaccountable.

“Speaking of dinosaurs,” Gingrich boasted after the election in 1994, “we eliminated three congressional committees, we cut the congressional committee staffs by a third and we adopted a resolution that we'll sell at least one office building that we currently occupy.”

Those congressional staff jobs that remain generally pay less.

“The greatest bargain the American people get are the staffs of the members of Congress,” said former congressman Barney Frank (D-Mass.). “Almost all of them are working for a lot less money at very hard jobs for very long hours.”

Because salaries often force junior staff members to share a house with several of their colleagues, those who hope to start a family often look for more lucrative work in the executive branch or at a lobbying firm. Lobbyists' expanding monopoly on knowledge and expertise extends their influence in Congress, as frazzled staffers often call K Street with basic questions about government or for help writing bills.

“Many people are introducing, just nonchalantly, amendments that come from the direction of special interests,” said Leach, the former Republican congressman from Iowa. “A member has no idea what all the implications are.”

If not lobbyists, rank-and-file members are relying more on congressional leadership and their staffs. Personal offices in the House have emptied out, but the speaker, the majority and minority leaders, the whips and their deputies have more resources. Those lawmakers' dedicated staffs have increased by half since 1995.

“This is just another way that power has really gone more to leadership and away from individual members,” said Rep. Daniel Lipinski (D-Ill.), who, with Rep. Darin LaHood (R-Ill.), has proposed legislation that would establish a committee to debate possible overhauls to Congress.

“In Congress, if you have the staff, if you have the expertise, you have people who can get things done, and that makes a big difference,” Lipinski said. “The ability to hire staff has a tremendous impact on what you are able to do, and that’s something, from the outside, I don’t think people see or understand.”

Members are less likely to support their argument with informative, detailed graphs, complained a senior Republican aide to a Senate committee. “You don’t see charts anymore,” the aide said. “You don't see people with graphs anymore.”

Real intellectual engagement and the give and take of the democratic process can be rewarding in themselves, and those aspects of the job are still enough to keep many aides on the Hill despite the low pay.

These days, though, some veteran staffers complain the joy has gone out of their work. There is less time to learn about the issues, to debate their friends on the other side and to come up with clever solutions to their constituents' problems.

“It’s a much less satisfying place to work than when I was there,” said Richard Hall, who was a legislative assistant to former senator Thomas A. Daschle (D-S.D.) 30 years ago and is now a political scientist.

The dearth of smarts among lawmakers has worrisome consequences for ordinary Americans. Meanwhile, on the Hill, the change has ruined all the fun.