Democrats' victories on Tuesday night wrested control of Congress from the Republican Party and will usher in a new era of Bay State influence over national politics.

Massachusetts politicians have hardly been absent from the national stage, but the Bay State's past dominance of the House has waned since the days when the late Tip O'Neill, a Cambridge Democrat, presided over the chamber in the 1980s. With the balance of power shifting back to the Democrats two years in the Trump administration, two Massachusetts congressmen are poised for powerful committee chairmanships and another member of the delegation is making a move for the fifth-highest position in leadership.

Rep. Richard Neal, of Springfield, expects to become chairman of the House Committee on Ways and Means, and Rep. James McGovern, of Worcester, is slated to become chairman of the House Committee on Rules.

Ways and Means has jurisdiction over taxation as well as pensions, Social Security, welfare, trade, tariffs, Medicare and some elements of Medicaid. Neal plans to hold hearings on the recent tax cuts and advance an infrastructure bill next session.

Whether those tax cut hearings will result in any legislation, it is too soon to say, said Neal.

The Rules Committee, where McGovern became the ranking Democrat after the death of New York Congresswoman Louise Slaughter in March, shapes the floor debates on every major piece of legislation.

"Every bill that goes to the House floor goes through the Rules Committee," McGovern said. "So you get to watch out for Massachusetts interests — to make sure that they're not trampled on, to make sure we can advance our goals."

Rep. Katherine Clark, of Melrose, who is a senior whip and helped lead Democrats' efforts to regain control of the House, is running for vice chair of the Democratic Caucus, which is four rungs below the speaker on the leadership chart. The other candidate in that contest right now is Rep. Pete Aguilar, of California. The election will be held in a closed Democratic caucus around Nov. 28 or 29, according to Clark.

While McGovern backs Clark for the leadership post and supports California Rep. Nancy Pelosi to continue leading the party in the House. Rep. Seth Moulton, another member of the Bay State delegation, hopes to oust Pelosi.

"I think it's time for new leadership in the House. It's time for a new generation of leaders in our party," Moulton, of Salem, told reporters Monday. "If we answer this call for change in this election by reinstalling the same status quo leadership that has presided over several losing elections for Democrats, that's a horrible impression."

According to Moulton, who said he would not vie for the top spot in the House, there are "a number of people working behind the scenes right now" to challenge Pelosi, though no one is campaigning publicly.

What the shuffling of offices and responsibilities on Capitol Hill means for Massachusetts business owners and others in the state depends in large part on the relationship between Democrats in the House and Republicans in the Senate and the White House.

"The Massachusetts delegation certainly stands to gain influence, but what happens with that influence is really unknown and dependent upon a lot of other factors," said Chris Geehern, executive vice president for public affairs and communications for the Associated Industries of Massachusetts. "Having our legislators chair committees and have broader influence is certainly a good thing. The larger context, however, is what does that get you? If Congress is going in one direction, and the president's going in another direction, and never the twain shall meet, then that influence is a little bit muted."

There are opportunities for both cooperation and conflict between Congress and the White House. The Ways and Means chair can request the president's personal tax information from the treasury secretary and the Internal Revenue Service, according to Neal, who plans to do that, though he is unsure whether the president would direct the agencies to comply.

President Donald Trump's decision during the 2016 campaign to break with decades of precedent and keep his tax returns private has raised alarms among ethics watchdogs and nurtured conspiracy theories about the president's income sources.

"To ask for them is the easy part," Neal said, adding, "I'm anticipating given the nature of the campaign that this is likely to end up ... [as] a legal matter. I just hope the president would do it on his own."

Neal also wants to tackle a troublesome multi-employer pension problem that has been brewing for years, consider the president's proposed overhaul of the North American Free Trade Act, and craft a bill to finance infrastructure projects around the country, where Democrats might find some common ground with the president.

With the ascension of Neal and McGovern, the congressional power-base in Massachusetts would lie to the west of Boston, and Neal said he would ensure that those areas of the state reap benefits from any major federal transportation bill.

"There are a series of transportation needs across the state, and I intend to make sure that Western Mass and Central Mass are included," said Neal. He specifically cited a "priority" of his: a proposed passenger rail project that would extend service beyond Worcester to Springfield and Pittsfield.

Neal said he would also wield his clout to protect Medicare financing for the state's health care industry, a major employer that serves scientific and medical needs for people around the world.

On the Rules Committee, McGovern said, he wants to return to the process where committees hold hearings on big bills before they reach the floor — something that Republicans bypassed to take votes on tax cuts and a health care overhaul, the latter of which failed in the Senate.

"We shouldn't be afraid of a fair fight, and so that means even some ideas that we may disagree with ought to be in order for debate," McGovern said. "So I want to change dramatically the way the Rules Committee does business."

Neal's position within House leadership could be a boon for other members from Massachusetts and the rest of New England, and Neal, who is the dean of the Bay State delegation, said it would be important to him for members from his area to receive choice assignments.

"We've made sure that everybody is positioned quite well on their committees," Neal said. "Your committee assignment is destiny in Congress."

The nine-member Massachusetts House delegation will include three women (up from two in the last Congress) two first-term members, and the state's first black woman in Congress after Boston City Councilor Ayanna Pressley beat Rep. Michael Capuano in the Democratic primary.

"What we are issuing here and now is a mandate for hope," Pressley said in a speech Tuesday night.

Neal said it would be important for Capuano's position at the top of the subcommittee on railroads, pipelines and hazardous materials be taken over by someone from the region. Jim Brett, president and chief executive officer of the non-partisan of the New England Council, a regional business lobby, suggested that Pressley should try to succeed Capuano on the Committee on Transportation and Infrastructure.

"With Mike leaving, we have no member [from] New England on Transportation," Brett said. "We need somebody on Transportation, because I think this is going to be one of the first bill."

Democratic control of Congress could also spell a return of earmarks, a system by which Congress directs federal spending to specific projects rather than leaving the decision making up to the administration. Neal said he supports the use of earmarks as long as the process is transparent, though rampant scandals and abuse of this process a decade ago would make their return controversial in the House.