It’s a possibility many Republicans speak of only in whispers, and Democrats are just now beginning to face. After passionate and contentious fights over health care, the environment and taxes, could Democrats lose big — really big — in next year’s elections?

Ask them about it, and many Democrats will point to the continued personal popularity of Barack Obama. But that’s not the story. “I think what’s going to happen is Obama’s going to be fine, and the Democrats in Congress are going to get their asses kicked in 2010,” says one Democratic strategist who prefers not to be named. “This is following a curve like the Clinton years: Take on really controversial things early, fail, or succeed partially, ask Democrats to take really tough votes, and then lose. A lot of guys are going to get beat, but the president has time to recover.”

Most Republican hope focuses on the House of Representatives, but even there they have a huge job ahead. Democrats control 256 seats, and Republicans 178. Forty seats would have to change hands for Republicans to take charge.

On the other hand, 52 seats turned over when the GOP won the House in 1994. And even if Republicans don’t get the 40 they need in 2010, they could dramatically narrow the gap between the parties, giving Speaker Nancy Pelosi and the Democratic leadership less room to operate.

The polls are definitely moving in the GOP’s direction. Just look at the Real Clear Politics average of the generic ballot question, which asks whether, if the election were held today, you would vote for your local Democratic or Republican candidate for Congress.

In recent weeks, poll after poll has shown Republicans neck and neck, or even ahead, of Democrats. Even a National Public Radio survey found Republicans in the lead.

Republicans were sensing momentum earlier in the summer, but events of the August recess — specifically, the town-hall meetings in which opponents of the Democratic healthcare-reform plan have turned out in force — have changed their view. “This month has opened our eyes,” says one plugged-in House aide. “We’re seeing real people who are fired up who weren’t engaged before — the first time we’ve had a popular movement that could really benefit us electorally.”

Rep. Tom Price, the Georgia congressman who heads the House Republican Study Committee, points to what he calls the fatal combination of Democratic overreaching and arrogance. “The American people like checks and balances, and right now they don’t see any checks and balances in Washington.”

Not long ago, some Republicans were worried about becoming a permanent minority party. They may not win in 2010, but they feel as if they’re back in the game.

(Byron York is chief political correspondent for The Washington Examiner.)