A shock surge in U.K. election for David Cameron's Conservatives and the SNP's near clean sweep in Scotland revives the spectre of a possible British breakaway from Europe - and the break-up of Britain itself. (Reuters)

It was both energizing and bracing to watch the election returns roll in here Thursday night and into the early hours of Friday — energizing because the unfolding story bore little resemblance to the polls and forecasts; bracing for the very same reason and for what that said about all the pre-election analysis.

Public polls — and they were many and often — predicted a wholly different result. What the country was told to expect was the second hung Parliament in a row, and the prospect of tortuous negotiations and maneuvering to construct a new government.

Instead, the Conservative Party under Prime Minister David Cameron produced a stunning victory, giving his party its first outright majority since the Tories yielded power to Tony Blair’s New Labor Party in 1997. Cameron didn’t call it the “sweetest victory” of all for him and the Conservatives for no reason. Rather than falling back in strength after five years in power as the head of a coalition government as might be expected, Cameron was able to enlarge his party’s numbers, to 331 seats in the 650-seat Parliament.

Cameron emerged politically and personally strengthened, if nonetheless left to deal with the huge challenges the election so aptly defined and highlighted, from the place of Scotland in what could be an increasingly divided United Kingdom, to Britain’s future place in the European Union and the world. With a slender majority and a potentially rebellious back bench, his leadership could be constantly tested as he tries to sort these out.

In contrast to the Conservatives, the Labor Party was left shattered by the final results, with a 99-seat deficit in Parliament, its traditional stronghold in Scotland in the grip of the Scottish National Party and its top two leaders now on the sidelines.

Party leader Ed Miliband, who on Thursday thought he might become the next prime minister even if his party had won fewer seats than the Conservatives, resigned his post on Friday morning after accepting responsibility for the losses. Ed Balls, who was the party’s chief economic minister and who had been in party power circles for two decades, was dispatched from power by the voters in one of the day’s biggest surprises.

As the party members begin the search for a new leader, they undoubtedly will go through a painful period of introspection about who they are and why they failed so badly. The unity they presented during the election will give way to a debate about whether they strayed too far from the Blairite center or were insufficiently robust with a more left-leaning message — or whether they were simply the victims of extraordinary circumstances playing out in Scotland.

Elections are often about the combination of fundamentals, personalities and performance. This election was no different. One key to Cameron’s victory was his focus broadly on the most fundamental of all issues, the economy and, particularly, the improvements that have taken place during his leadership. Incumbency can be a powerful asset during times of a rising economy, and he made the most of it.

His austerity policies had inflicted pain and produced fierce debate about fairness, but he was able to point voters to the gains and the hope that they would continue with Conservatives in power, while warning against going back to a Labor Party he portrayed as profligate in its spending habits and whose new leader he sought to portray as unreliable and untrustworthy with the country’s economic future.

Cameron successfully made central to the debate the fear of rising deficits under a prospective Labor government vs. allowing his party to finish the job of restoring the economy. To soften the edges of his own party against charges that it favored the rich at the expense of others, he also offered a variety of new spending initiatives — though without fully explaining how he would pay for them.

Labor under Miliband had moved left from its Blairite domestic policy moorings, with a sharper critique of capitalism. But the message attacking rising economic inequality and insensitive Conservative policies proved less effective with voters than Cameron’s emphasis on rising overall growth.

Public opinion polls and other signs before the election suggested that the fairness issue could cut against the Conservatives in the short and long term — and I wrote a week ago that the Republican Party might have to take a lesson from that. The election results suggest something different, at least here and now.

Some Republicans, former House speaker Newt Gingrich among them, think Cameron’s victory proves that if Democrats follow the wishes of the Elizabeth Warren wing of their party, the GOP will have a major opening to exploit in 2016, if they can present a strong, and positive vision for the economy and the middle class.

It will take more time to understand all the reasons for what happened here and the parallels for U.S. politics. But the Conservative victory here should be read by Democrats as evidence that their own economic messaging will need work heading into 2016, that it might not be as simple as claiming the deck is stacked, calling for an increase in the minimum wage and expecting voters to follow.

Labor suffered as well from the deficit in how many people judged the leaders of the two main parties. At a time of deep disaffection with politics and politicians, neither Cameron nor Miliband was especially admired. But in comparisons between the two, Cameron generally came out ahead — somewhat better liked and generally preferred by a decent margin as the next prime minister. That no doubt is a lesson that translates across borders.

Miliband performed admirably during the campaign, winning praise even from some on the other side as a stronger and more polished leader than pre-election caricatures. But the short campaign was not enough to fully shake off the past — his own or his party’s. One critical moment came a week before the election, when he denied that Labor had spent and borrowed too freely when it was last in power. The audience groaned, and his credibility took a hit.

On Election Day, I was in west London talking with voters as they left a polling station at an elementary school. One woman, in her early 60s, came out and said she had voted Labor, as she always had. She found the Tories “unjust” and believed her party was committed to fairness. Then she said of Miliband: “I don’t think he’s a good leader of the Labor Party. I think it is true that he is weak.” That didn’t deter her from supporting the Labor Party, but no doubt others who saw him that way held back.

There was little before the election to suggest the Conservatives could win more than 300 seats, let alone 331, though there were hints. On Election Day, the Conservatives’ internal modeling, directed by Jim Messina, President Obama’s 2012 campaign manager, showed them on course to win at least 312 seats. Findings from 18,000 online interviews by SurveyMonkey provided to The Washington Post that morning showed the Tories with a six-point lead over Labor. Everything else predicted a muddle.

Then on Thursday, the voters delivered a shock — to the politicians here, to the pollsters and to those who follow the polls. That brought a thrilling night of vote counting and more exhilaration and disappointment across the parties than anyone could have anticipated. But the aftermath also demands a search for answers and understanding and an appreciation that the complexities of an age of frustration, anxiety and political disaffection leave no politician, party or analyst safe or secure in their assumptions.