President-elect Barack Obama's victory left no doubt that his campaign reached, and resonated with, a broad swath of America. In Electoral College votes, Mr. Obama topped his Republican rival, Senator John McCain, by more than a two-to-one margin. Political experts point to several factors that made Mr. Obama's win both probable and powerful, and reasons why McCain couldn't overcome him. VOA's Jeffrey Young reports.

Headlines of New York City newspapers the day after the US presidential election, 5 Nov. 2008

Barack Obama's victory has given the Democratic Party control of both the White House and Congress for the first time since 1992. Political observers say the Obama campaign combined a keen ability to capitalize on external circumstances with strong organization and discipline.

Nathan Gonzales at the Rothenberg Political Report says Americans were ready for Obama's message of "change."

"After eight years of George W. Bush, the American electorate was really primed for change," he said. "They were dissatisfied with the direction of the country, and were ready for something new."

Georgetown University government professor Mark Rom says the other components also worked. "They had a clear, consistent message that was persuasive to the American public that Obama was on their side, that he would work in their interests, and that he would do the right things for the middle class. Second, an incredible ground campaign, registering millions of new voters all across the country," Rom said.

Analysts say Mr. Obama's campaign excelled at using modern technology - such as cell phones, text-messaging and email - to reach voters and turn them out at the polls.

The deteriorating economy and sinking stock market left middle class voters fearing their life's savings were in danger.

Alex Burns at Politico.com says Mr. Obama reaped the benefit of the financial turmoil. "I think that the [Wall Street] financial crisis was the ultimate game-changer in this election," Burns said. "I think that crystalised in a lot of people's minds exactly how bad things were. And, for a candidate like Barack Obama, that was very fortuitious because he was the one running on a message of change."

The McCain campaign's failings also helped Mr. Obama, says Professor Rom. "He made mistake after mistake. His campaign appeared to be erratic," Rom said. "It never really developed a clear, consistent message that resonated with the public."

Pundits say McCain also could not separate himself from the unpopular Republican President, George Bush. 

Mr. Obama's choice of Senator Joe Biden as his vice presidential running mate helped deliver working-class Democrats and independent voters in key states like Ohio, Pennsylvania, and Florida.

But McCain's choice of Alaska Governor Sarah Palin failed to expand his appeal beyond a core conservative group. 

Observers say Mr. Obama's campaign reassembled the traditional Democratic Party coalition of big cities, labor, minorities, women, and the young. All are waiting to see if Mr. Obama will bring the same discipline and focus to his presidency.