Barack Obama picked up the support of another Democratic superdelegate in his nomination battle with Hillary Clinton yesterday, hours after her chief strategist was ousted from her troubled campaign.

In receiving the backing of Marga-ret Campbell, a Montana state legislator, Mr Obama has gained the support of 69 superdelegates since February 5 compared with Mrs Clinton, who has suffered a net loss of two. Mrs Clinton still leads by about 250 to 220 superdelegates but Mr Obama’s near-insurmountable lead among elected delegates appears to be swaying many more party officials to his side.

Mrs Clinton refused to answer questions about the resignation of Mark Penn, her senior strategist who has been at the heart of the Clintons’ political life since he was first hired by her husband as his White House pollster in 1996. Mr Penn, a polarising and unpopular figure in Mrs Clinton’s campaign who has feuded with many senior members of her camp, was forced out on Sunday night over his ties to an international free-trade deal that the former First Lady opposes.

The resignation is the latest troubling development for Mrs Clinton and her second shake-up in recent weeks. Patti Solis Doyle, her campaign manager, quit in February.

A race like a crackpot Dynasty

The contest between Barack Obama and Hillary Clinton matches any fiction

Multimedia

• Full coverage: US elections

BACKGROUND

• The ascent of Barack Obama, Mr Charisma

• Decay, jobs and guns fall under the spotlight

• Free trade: Clinton/Obama's mistakes

Related Links

• Petraeus enters presidential battlefield

• Rapid rise of Hillary's fortune

• Hillary Clinton: fibber in chief

It emerged that Mr Penn, who is chief executive of Burson-Marsteller, a giant PR firm, had met Carolina Barco, Colombia’s US Ambassador, to help to get a US-Colombia free-trade agreement through Congress. It is a deal that only last week Mrs Clinton said she opposed. With exquisite timing, President Bush called yesterday on Congress to pass the deal.

Free-trade agreements are fiercely opposed by many blue-collar workers who form a crucial part of the electorate in the next Democratic primary in Pennsylvania on April 22, where Mrs Clinton badly needs a big win. She spoke out over her opposition to the Colombia deal last week in a speech to a union audience in Philadelphia.

Mr Penn has been a lightning rod for critics since Mrs Clinton’s campaign ran into trouble last October, particularly over his early decision to focus on a limited number of big primary states. Yet until this week he has survived because of the Clintons’ loyalty to him. However, they were furious with him over his Colombia meeting and he was rapidly removed.

His resignation is unlikely to have a dramatic impact on strategy this late, but it will improve morale. A gruff, socially awkward figure, Mr Penn got into shouting matches with other senior staff. There was also resentment over the $11 million that his firm has been paid. His philosophy, spelled out in his book Microtrends, stressed “small, reasonable ideas over big, grandiose schemes”. It was an uninspiring message in a “change” election year.

Times Recommends

• Tehran cannot live up to its rhetoric
• The new unicycle that will ‘change the world’
• We cannot wish away Iran’s bomb