ANALYSIS:Democrats warily eye centrist 'flip-flops' as conservative Republicans get edgy, writes Denis Staunton.
AS AMERICANS celebrate the Fourth of July, marking the start of a six-week lull in the presidential campaign before the party conventions at the end of the summer, Barack Obama and John McCain are just a few points apart in most polls.
Three weeks after Obama wrapped up the Democratic nomination, he has failed to register a significant bounce while McCain's numbers remain consistent despite the Republican's unfocused and sometimes shambolic campaign.
Since his defeat of Hillary Clinton, Obama has moved swiftly to unite his party behind him, courting her wounded supporters and appearing at a love-drenched rally with his former rival in Unity, New Hampshire.
He has also moved sharply to the political centre, shocking some liberal supporters with apparent U-turns on everything from electronic surveillance to gun control and abandoning a promise to accept federal spending limits during the general election campaign.
Within the past two weeks, Obama has spoken in favour of allowing child rapists to be executed, expressed support for an expansion of gun rights and promised to expand President George Bush's programme that allows religious groups to deliver some federally funded social services.
Liberal bloggers are especially outraged by his support for a bill that gives immunity from prosecution to phone companies that facilitated Bush's illegal surveillance of US citizens. Most Democrats are relaxed about such flip-flops, however, and many welcome them as signs that their candidate is tough and ruthless enough to win in November.
Obama's dash to the centre stands in marked contrast to McCain's struggle to appease his conservative base while appealing to independent voters with initiatives on issues like climate change and the environment.
McCain acknowledged his campaign's lack of focus this week with a major staff shake-up that placed Steve Schmidt, who worked closely with Karl Rove in Bush's 2004 campaign, in charge of day-to-day operations.
While McCain shows signs of nervousness, the Obama campaign exudes confidence, already advertising in 21 states, including places like Alaska, Georgia and Nebraska, that have long been no-go areas for Democratic presidential candidates.
Obama's decision to opt out of the public financing system suggests that he is confident of raising much more than the $84 million McCain will receive from public funds.
On the face of it, Obama has every reason to feel bullish, especially where money is concerned. During the primary campaign, he raised almost $300 million, compared to McCain's $122 million.
The Democratic primary contest was expensive, however, and at the end of May, Obama had a cash-on-hand advantage over McCain of less than $12 million. Meanwhile, the Republican National Committee has been outraising its Democratic counterpart by a wide margin and independent groups are preparing to spend millions in support of McCain.
The political fundamentals favour the Democrats in November as Americans blame the Republicans and their unpopular president for collapsing house prices, the soaring cost of food and fuel and an apparently endless war in Iraq.
Obama believes he can transform the electoral map by winning states like Virginia, Colorado and Indiana but the race remains close in the traditional battleground states of Florida, Michigan, Ohio and Pennsylvania.
Obama is a more disciplined politician than his rival and the Democrat's campaign is formidably well organised but events this week showed that even the most carefully prepared plans can run aground.
Obama's big speeches on patriotism, faith and public service were overshadowed by a four-day dispute over remarks by one of his surrogates who suggested that McCain's military service didn't qualify him to be president.
McCain was shot down over Vietnam, imprisoned in Hanoi for five years, tortured and denied treatment for broken limbs and refused offers to be sent home before his comrades.
The ordeal may not count as executive experience but for most Americans it confirms McCain as a figure of unusual courage and integrity.
Obama remains a mystery to many voters and his recent policy shifts risk obscuring his image as a new kind of politician who rejects double-talk and political expediency.
For both candidates, the most important decision of the coming weeks will be their choice of running mate. Both are being coy, allowing various names to be floated without giving away anything about their own intentions.
The current favourite among pundits to join McCain's ticket is former Massachusetts governor Mitt Romney, who has the economic expertise the Republican candidate lacks and could win votes in Michigan, where his father was governor.
There is little enthusiasm within the Obama camp for bringing Clinton on to the Democratic ticket and much of the current buzz surrounds figures with national security credentials like Virginia senator Jim Webb and former Georgia senator Sam Nunn.
If the past few weeks have revealed anything about Obama, however, it is that he approaches November's election with cold political calculation and if the evidence next month suggests that he needs Clinton to win the White House, there can be little doubt what choice he will make.
• Denis Staunton is Washington Correspondent of The Irish Times