It’s been just 1,397 days since Democrats took the reins of power on Capitol Hill, but in a single day, they could see it come to an end.

Today’s midterm elections promise to bring about a historic power shift on Capitol Hill for the third time in as many cycles. With such a volatile electorate throwing power in Washington back and forth, by Wednesday the question could turn to how long the latest change will last and whether ‘wave’ elections will become the norm as voters continue to seek instant political transformation from their leaders.

‘Part of what’s happened is we’ve had three election cycles where we’ve convinced people that the system sucks,’ Democratic consultant Dave Beattie said Monday. ‘And they truly believe that the system sucks. So we’ve succeeded in convincing people of that, and now we have to live with their anger at being in a political system that sucks.’

As a result of the discontent with Democratic rule, House Republicans could see gains in excess of the 52 seats they picked up in 1994, the last time the GOP was swept into power. A tougher Senate field makes it likely that the House could flip without the Senate changing hands, which hasn’t happened since World War II.

Among the most-watched races tonight will be that of Senate Majority Leader Harry Reid, who was joined Monday by first lady Michelle Obama for the Nevada Democratic Party’s final get-out-the-vote rally. Reid drew the battle lines and asked the 1,200 activists to consider the price of failure.

‘I need you in the next few hours. Don’t let someone else work harder than you,’ he said. ‘You need to knock on an extra door. You need to make that extra phone call.’

These midterms are a stunning turnaround from four years ago, when voter anger at Republican control of the White House and Congress put Reid and Democrats in power.

On election night 2006, Speaker-to-be Nancy Pelosi (D-Calif.) described the results as a mandate ‘to restore stability and bipartisanship’ in Washington. That didn’t happen, but another Democratic wave in 2008 left the Republican Party in tatters, while Senate Democrats briefly enjoyed a filibuster-proof majority and used it enact historic and controversial health care reform.

During a speech to the Allen County Republican Party in Lima, Ohio, on Friday, House Minority Leader John Boehner ‘ the Ohio Republican who is set to become Speaker after an expected GOP sweep tonight ‘ struck a theme similar to Pelosi’s 2006 promise.

‘We have a Congress today that is so bottled up, so tied up in knots,’ he said. ‘There’s literally five people who start the process of passing a bill, and the same five people decide what the outcome is going to be of that bill. … It’s time to open up the process and allow all Members of the House of Representatives the opportunity to debate bills, to offer amendments to bills and truly represent their constituents. But we have to fix the Congress of the United States.’

However, even if the Republican wave turns into a tsunami, the results aren’t likely to be read as an embrace of the GOP but rather a rejection of where Democrats have taken the country.

‘If they do take [the House] back, it would be a mistake for them to view it as a mandate for them,’ one senior House Democratic aide said. ‘If things haven’t changed in two years, [voters] may do it to them too.’

Democrats clearly felt they had a mandate to enact their priorities after the 2006 and 2008 surges, and like many leaders before them, they took a long view toward their agenda by pursuing issues such as health care reform and a cap-and-trade system for energy markets.

And even though Democrats made an economic stimulus package the first item of business when they convened in 2009, voters appear poised to punish the majority for not taking a short-term, focused approach to the country’s ills.

‘A lot of voters think we did too much and didn’t focus on the economy,’ the senior House Democratic aide acknowledged.

But the aide added that many Democrats feel their missteps came in failing to pass a larger stimulus bill, given that many economists said the $900 billion that Obama proposed would likely be inadequate. In the end, concessions made to Republicans and centrist Democrats shaved the stimulus to $787 billion, a third of which was tax cuts.

‘I’m not sure what, if anything else, we could have done,’ a senior Senate Democratic aide said of the party’s attempts to address the recession and the slow recovery.

Republicans said that if they take control of the House, their strategy would build on the lessons they have learned from the Democrats and their own loss of the majority in 2006, which many attribute to their abandonment of small-government, fiscally conservative roots.

‘We have some perspective from these last few Congresses,’ said one House GOP aide with knowledge of leadership’s thinking. ‘But this Congress in particular was a mess. It was all over the place. It wasn’t focused.’

Focused or not, the massive ‘ and frequent ‘ political shifts have some wondering whether politics has become a tidal affair, with sweeping change becoming the norm. It’s a theory born from the never-ending campaign season, the 24-hour news cycle and an electorate that has little patience for gradual change.

Of course, a split in party control between the House and Senate might make it harder for another wave election to develop in 2012, simply because voters may find it hard to blame one party or the other.

Both sides could take credit for any good news and point the finger to the other chamber or the president if the economy and jobs situation continue to be stuck in a rut. Another argument against a fourth wave election is that 2010 looks likely to serve as a course correction after Democrats extended their gains well beyond the traditional places where the party has been successful.

Senate Minority Leader Mitch McConnell told Roll Call on Monday that while the mood of the country may be similar, this year’s wave favoring Republicans is not the same as the GOP’s 1994 landslide or Democrats’ 2006 victories.

‘I think the issue set is a little different. … Spending and debt are much more important,’ the Kentucky Republican said. ‘There’s [also] a genuine fear about the direction of the country this year, which I don’t think was the case in ’94 or 2006.’

But many political insiders predicted the electorate will remain fickle and hard to please.

‘The days of decades of a majority in Congress are long gone’ Republican new media consultant Brian Donahue said. ‘People are more able to hold their elected officials accountable on a day-by-day basis because of the amount of the news and information they have access to as well as their ability to communicate on issues of concern and to organize like-minded voters in easier ways.’

The power of that organizing ability was epitomized this cycle by the rise of the tea party movement, a group that remains poised to be an influential force once again in the 2012 primaries and general election.

Speed also took on increased importance when it came to Congressional campaigns this cycle. Candidates were made or ruined on their ability to quickly tailor their messages to different audiences in response to breaking news or reports from field operatives.

‘If you’re not talking about the latest jobs numbers and what’s going on with our economy, you missed the point by missing the important news of the day,’ Donahue said.

Democratic officials still publicly claim that they have a chance of holding the House and claim that their turnout operations could save the party from major losses. But in recent weeks, party operatives have been increasingly willing to admit that the political die has been cast. Most polling points to Republican gains well in excess of the 39 net seats needed to flip the House, and the real fight now appears to be whether the GOP can also take the Senate and complete what would be a remarkable comeback in just four years. Most pundits have predicted an at least eight-seat gain for the Senate GOP, shy of the 10 needed to regain control. But a complete GOP takeover of the Senate is not out of the question given the volatile electorate.

‘I think our politics is going to remain fundamentally divisive. I don’t think that that changes,’ Beattie predicted. ‘If you have both sides trying to appeal intensely to a base, then neither side is successful at building a coalition that wants results and outcomes. If that doesn’t occur, then yeah, I think we’re absolutely going to see the same politics continue.’

John Stanton, Jackie Kucinich and David M. Drucker contributed to this report.