WASHINGTON - Winning the White House might not be enough for Hillary Clinton.
If she wants to follow through on her promises, it will also take a Democratic surge at the other end of Pennsylvania Avenue.
Consider President Obama. With a Democratic Congress in his first two years in office, he pushed push through a sweeping health law, massive financial stimulus, and major banking legislation. Now, he can't even get a hearing on a Supreme Court nominee.
That's why Clinton is aiming not just to beat Republican Donald Trump, but to bring on a wave that delivers Democrats the Senate and at least narrows the GOP majority in the House.
The Senate is within reach: Democrats need to gain five seats to take the chamber, four if they win the White House and control the tie-breaking vote.
They appear all but certain to gain two seats, leaving six tight races - including in Pennsylvania - likely to determine who controls the Senate when the next president takes office.
Democrats need to add 30 seats to capture the House - a long shot, even if they seem poised for gains.
The consequences could be enormous.
"If Republicans keep even just control of the House, the possibilities instantly narrow for what [Clinton] is able to achieve," said Julian Zelizer, a Princeton University political historian. "Congress really plays a huge role in determining what a president's legacy will be."
While Democrats hope a big Clinton win can help them prevail, new questions raised Friday about an FBI email investigation threatened to blunt her momentum. If her margins shrink in key states, it could damage Clinton's hopes for a down-ballot wave.
In Philadelphia recently, Clinton blasted Pennsylvania Republican Sen. Pat Toomey, who's running for reelection against Democrat Katie McGinty. Vice President Biden continued the push last week in Pittsburgh.
"When she gets elected, God willing, she needs a Democratic Senate," Biden said, calling the chamber "almost nonfunctioning" under Republicans.
And in Bucks County on Wednesday, vice presidential candidate Tim Kaine tied Clinton's agenda to electing McGinty.
Similar scenes have played out in other Senate battlegrounds. In Florida, for example, Obama lashed out at Republican Sen. Marco Rubio in a recent stop.
Clinton has urged donors to steer money to critical Senate races, CNN reported, and a Clinton-allied super PAC recently launched ads attacking Toomey and New Hampshire Sen. Kelly Ayotte.
Republicans have told voters a GOP-led Congress is a safeguard against a Clinton win.
While Republicans may split on Trump, "what we all agree on is we need 51 Republican members back in the U.S. Senate," Sen. Thom Tillis (R., N.C.) said last week as he campaigned with Toomey in Philadelphia.
Soon after came a new Toomey TV ad proclaiming, "Pat Toomey will fight Clinton's liberal agenda."
Democrats look certain of gaining Senate seats in Illinois and Wisconsin. Republicans look strong in tough races in Ohio and Florida.
That leaves six contests likely to decide control of the chamber, with Pennsylvania and New Hampshire atop the list. Both have Republican incumbents, and both are in states Obama won twice.
After that, Democrats are aiming for gains in Indiana, Missouri, and North Carolina, while hoping to hold a seat in a hard-fought Nevada contest.
The margins are razor thin.
Some Republicans worry that Clinton's polling edge in the Keystone State and her superior get-out-the-vote operation could sink Toomey.
He "certainly has an uphill battle right now," said one GOP operative familiar with the race.
Others in both parties say the contest - and the overall fight for the Senate - could go either way.
"A Hillary Clinton presidency would be bad enough, but it would be far worse with a Democratic majority in the Senate," said Ian Prior, spokesman for a Republican super PAC, the Senate Leadership Fund, that announced $25 million in last-minute ad buys last week, including $5.2 million in Pennsylvania.
Few analysts see enough of a tide to hand Democrats the House.
They have a "great" shot at picking up 15 to 20 seats, said David Wasserman, an analyst for the Cook Political Report, an elections forecasting outlet, but "the quality of their opportunities drops after that."
Democrats are trying to anchor GOP candidates to Trump, hoping the divisive nominee can help them win in moderate districts like Pennsylvania's Eighth, based in Bucks County, and North Jersey's Fifth.
The Bucks race, for an open seat, is excruciatingly close, both sides say.
Democrats appear to be in strong position to capitalize in North Jersey, where GOP Rep. Scott Garrett came under fire for reports that he refused to donate to Republicans' House campaign arm because of its support of gay candidates. Many of his biggest donors backed away in response, sapping his financial strength.
Meanwhile, his Democratic challenger, Josh Gottheimer, has been a prolific fund-raiser, giving him the money needed to compete in the New York media market.
After those two seats, however, Democrats' next target in this area is a long shot: Pennsylvania's 16th District, based in Lancaster County, where Rep. Joe Pitts is retiring.
Weak candidates have left Democrats unable to mount serious challenges for moderate suburban seats based in Chester County and South Jersey, where Trump's drag might have given them a chance.
The most likely outcome, according to most forecasters, is a closely divided Senate and shrunken Republican edge in the House.
That might lead to more gridlock.
Democratic gains in the House will likely come at the expense of centrist Republicans - leaving more power in the hands of the conservative bloc, which has fiercely opposed compromise, said Sarah Binder, a political science professor at George Washington University.
"We don't have a lot of episodes of split party control of Congress, but the recent episodes we do have aren't great recipes for getting a lot done," Binder said.
Democrats may want to score bipartisan accomplishments to show that a Clinton presidency works, she said, but Republicans will have reason to resist.
"If you think you're going to regain control of the government" in 2018, she said, "it kind of diminishes incentives to come to the table."