For the second time in eight years, Arizona Sen. John McCain failed in his bid to reach the White House. In the coming days and weeks television analysts, newspaper pundits, and political scientists will likely try to unravel the reasons McCain fell short this year. But a few key causes may already stand out.

There is little doubt that Barack Obama ran one of the best organized campaigns in U.S. presidential history, and the Democrat and his staff were largely responsible for McCain's loss. But McCain, himself, did not help his cause.

By the closing days of the election campaign, analysts noted that he was unable to give voters a consistent, pro-active message. For much of the campaign, it appeared McCain was constantly trying to persuade voters about why Obama was not fit for the White House. But political pundits said he did not give them clear enough reasons to vote for him. They noted that his campaign employed "tactics" without an overall strategy.

But McCain also made specific tactical mistakes. Here are some of the other reasons McCain may have failed in his bid for the White House.

Mid-September economic meltdown

Heading into the general election, McCain's strongest appeal with voters was his national security credential. But Iraq- and terrorism-related issues were largely pushed to the backburner in mid-September when the financial meltdown hit.

McCain, who had previously admitted that the economy was not his strong suit, tried to seize the moment by suspending his campaign. He even threatened to withdraw from the first presidential debate so he could go to Washington to help Congress hammer out a financial-sector bailout package. Just days later, he was back on the campaign trail, even though Congress hadn't yet come up with a bailout package, and he showed up for the debate.

The Democrats took the opportunity, portraying the 72-year-old senator as an "erratic" and out-of-touch politician. The Democrats hammered home the erratic message throughout September and October, reminding voters on a regular basis that just days before McCain suspended his campaign, he had said the fundamentals of the economy were strong.

In an election year when the economy came to dominate the issues, Obama's message that McCain doesn't "get it" appears to have resonated with voters.

Picking Sarah Palin

McCain's choice of Alaska Governor Sarah Palin as his vice presidential pick in late August gave the Republicans an initial boost in the polls. It also helped energize the base, which, until then, had been cool to the senator's presidential bid.

But once the media had the opportunity to interview the former beauty queen and small town mayor, her favourability ratings dropped dramatically. In an interview with ABC News, Palin appeared not to know what the "Bush Doctrine" is. Another television interview, this one with CBS, also didn't go well, with the governor often appearing confused about major issues and offering rambling, incoherent answers.

The woman who had sold herself as just an "average hockey mom" also ended up in a minor scandal when it was revealed that the Republican Party paid US$150,000 to outfit the governor.

But worst of all for McCain, more and more voters increasingly saw Palin as a liability. Independents, conservatives and even party faithful began to openly question the senator's judgment in picking a vice presidential candidate who appeared to be out of her depth in national and international affairs.

Negative attacks

Many conservatives have suggested that McCain's refusal to use the Rev. Jeremiah Wright issue handicapped his campaign. The fiery preacher became a lightening rod during the Democratic primary with what critics said were "anti-American" sermons.

But McCain had told his campaign the Wright-issue was out of bounds because of the racial undertones of attacking an African-American candidate because of his links to a black church and preacher. Some analysts, particularly conservative talk show hosts, have said this was a costly mistake.

But negative campaigning appears to have been even more costly to the McCain campaign. When it used Obama's association with former Weather Underground member and current college professor William Ayers as an example of how he was "palling around with terrorists," polls showed voters didn't agree.

Similarly, voters didn't believe the McCain campaign when it alleged that Obama wanted to teach sex education to kindergarteners. (He didn't, but supported a comprehensive state bill, which included teaching young children about families.)

George Bush ties lingered

Throughout most of the primaries and much of the general campaign the Democrats repeated a common refrain, arguing over and over again that McCain represented U.S. President George Bush's third term. The strategy appeared to be a good one for the Democrats, considering Bush's approval ratings had dipped below 30 per cent in some polls.

But it wasn't until the third presidential debate that McCain publicly separated himself from the Bush administration, when he turned to Obama and said: "I am not George Bush."

Too little, too late, said one Washington insider.

"McCain's belated criticisms are akin to Thomas Jefferson writing the Declaration of Independence in 1815," wrote Salon Magazine's Washington bureau chief, Walter Shapiro.