The most expensive presidential election in U.S. history brought the nation full circle, back to where it all began.

Thanks in part to a U.S. Supreme Court decision that unleashed untold millions of corporate dollars into the electoral process, a breathtaking $6 billion was spent on the campaigns of President Barack Obama and Mitt Romney, nearly twice what was spent in the divisive 2000 campaign.

But on Tuesday it ended with Obama remaining in the Oval Office, with Democrats retaining control of the U.S. Senate and Republicans holding on to the House of Representatives.

Obama seemed headed for re-election even before polls closed in California, having claimed key swing states of Pennsylvania, Michigan and New Hampshire, leaving Romney having to win both Florida and Ohio to have a chance of reaching the coveted 270 electoral votes.

But it was not to be. By 8:15 p.m. Pacific time, it was clear that Obama was going to win Ohio and was en route to winning re-election outright.

We have no complaints with this outcome. It's our belief that amid one of the most challenging economic downturns in this nation's history, President Obama has performed admirably and showed himself deserving of a second term. Moreover, his victory is a repudiation of Republican attempts to pin the trials of the past four years solely on him and his efforts to avert a deeper crisis.

Nonetheless, Obama remains commander of chief of a torn nation, with a divided Congress and a Republican Party dominated by staunch critics of his policies. His challenges will be greater still if the final results shows him losing the popular vote, which, as of late Tuesday, remained a possibility.

Obama's most immediate challenge, even before he takes the oath of office for a second time in January, will be to find a way to bring Congress together to avoid the "fiscal cliff" that is fast approaching at the end of December. Our hope is that, with the election behind, a compromise can be found to prevent dramatic tax increases and spending cuts that would otherwise automatically occur, potentially pushing the country back into recession.

But the story of Tuesday is not just about Obama's victory. It's about the failure of the Republican Party to maintain the momentum of victories in 2010 to recapture the White House and pick up just four seats in the Senate — all amid an economy that was ripe for GOP gains.

But it did not occur. Just as the Obama needs to take seriously the challenges before him, likewise Republicans need to take a sober look at how they lost this election. It seems clear that the GOP lost the heart of the nation — and this election — by hewing to the hard-line rhetoric and objectives of the tea party, and with an entrenched opposition to work in any bipartisan fashion with the president and Democrats on Capitol Hill.

Two years ago last month, in an interview with National Journal magazine, Senate Minority Leader Mitch McConnell explained that "the single most important thing we want to achieve is for President Obama to be a one-term president." And it's tactics for achieving that goal was to do nothing to help the president, and by extension, the nation.

Voters are left to hope that Republicans will find a new approach. Going forward, America can't afford more entrenchment. Moreover, voters, as they made clear on Tuesday, don't want it.