WASHINGTON — A barrage of negative ads, more than $2 billion in spending and endless campaign stops all come down to this: Americans likely will elect a Congress as divided as the one they’ve been ranting about for two years.

In Tuesday’s voting, Republicans are poised to hold the 435-seat House, with Democrats expected to gain a small handful of seats at best from roughly 60 competitive races but fall well short of the net 25 needed for the majority. House Speaker John Boehner, R-Ohio, is poised to wield the gavel again.

Additional Photos

In this Sept. 21, 2012 file photo, House Speaker John Boehner of Ohio meets with reporter on Capitol Hill in Washington. A barrage of negative ads, more than $2 billion in spending and months of campaign stops come down to this reality: Americans will wake up Wednesday with likely the same divided Congress it had that past two years. Republicans are poised to keep their hold on the House, Democrats are most likely to narrowly hold the Senate. (AP Photo/J. Scott Applewhite, File)

Senate Democrats are likely to maintain their narrow advantage as two Republican candidates’ clumsy comments about rape and abortion could cost the GOP Indiana and dampens its prospects of winning Missouri — two major roadblocks in the Republican path to the majority.

Republicans hoped the math would work in their favor — Democrats are defending 23 seats, the GOP 10 — but solid Democratic recruits and the close presidential race, added to the GOP candidate stumbles may ensure that Nevada Sen. Harry Reid remains majority leader.

“That’s extremely frustrating for what everyone thought was a Republican advantage,” Ron Bonjean, a Republican consultant and former top Capitol Hill aide, said of the developments in Indiana and Missouri.

No matter who wins the presidency — President Barack Obama or Republican Mitt Romney — the nation’s chief executive will be dealing with a Congress no closer to bridging the ideological chasm and showing no inclination to end the months of dysfunction. Tea party numbers are certain to tick up in the Senate with Republican Ted Cruz heavily favored in Texas and Deb Fischer looking to grab the Nebraska seat.

In the House, the movement that propelled the GOP to the majority in 2010 will be even more emboldened even if a few of the big-name tea partiers lose.

Sal Russo, head of the Tea Party Express, likened the group to the anti-Vietnam War movement of the late 1960s and early 1970s that he said remade the Democratic Party. He envisions the same with the GOP.

“In the sense that the anti-war movement brought out millions of people that had not been involved in politics and they became engaged in a material way,” Russo said in an interview as he headed to what he expects will be a victory party for Cruz in Texas.

The Democratic Party, he insists, has never been the same and neither will the GOP after the influx of tea partiers.

When the Senate votes are counted, moderate Republicans and Democrats from Massachusetts and Montana could be gone, leaving the chamber with just a handful of the lawmakers inclined to reach across the aisle. Republican Sen. Olympia Snowe of Maine decided to retire earlier this year, frustrated with the partisan gridlock in Congress.

New England’s three other GOP senators are New Hampshire’s Kelly Ayotte, Maine’s Susan Collins and Massachusetts’ Scott Brown, now an underdog against Democrat Elizabeth Warren in a race for the late Sen. Edward M. Kennedy’s seat.

“The few Republicans who are in office in New England are an endangered species,” said veteran Democratic strategist Dan Payne, who is working for independent Angus King. “Their party has shifted so far to the right.”

King is favored to win the three-way race for Snowe’s seat.

A Bloomberg poll in September found that 55 percent of Americans said Congress will continue to be an impediment no matter who is elected president. Just 32 percent said Congress would get the message and work together.

Democratic strategist Steve McMahon said he worries that with a divided Congress “we can probably expect hyper partisanship and gridlock everywhere. It seems like Americans can expect more of the same.”

The other certainty is neither Obama nor Romney will have much of a mandate based on the razor-thin presidential race and the likelihood that the majority party in the Senate will be nowhere near a filibuster-proof majority.

“Neither candidate will be able to claim that voters endorsed a clear and specific plan for balancing the budget because neither of them offered such a plan,” said John J. Pitney, a professor of American politics at Claremont McKenna College.

Republican strategist Terry Holt said a newly elected president who has the will could put their mark on policy and make some significant changes.

“But there is so much ideological division that you will have to risk your political life to get something done in the next Congress,” Holt said. “It is an all-or-nothing proposition by virtue of the divided nature of the country. You have to stick your neck out if you’re to get anything done.”

Weeks before the January inauguration, Congress will have to decide what to do about a $607 billion so-called fiscal cliff: the combination of expiring Bush-era tax cuts and automatic, across-the-board spending reductions to domestic and defense programs. Economists warn that no action will plunge the country into another recession.

“At the end of the day, you have so many ticking time bombs,” said GOP strategist John Feehery. “Having just a complete gridlock is not an acceptable solution.”

Congress may decide in the lame-duck session to delay the major decisions to early next year, especially if Romney wins the presidency. But they can’t put off economic decisions for too long.

“The road to fiscal perdition is a cul-de-sac,” Pitney said.