CHICAGO: One was gone within hours. Another lasted a few days. The most famous hung on for weeks. In dealing with associates who have dragged him into controversies, Barack Obama has shown great patience with a longtime friend, but much less forbearance with those whose ties are weaker.

The varying approaches suggest the likely Democratic presidential nominee is feeling his way on how to handle staff crises. He also is learning that it’s one thing to set high standards for conduct, and another to enforce them in the imperfect worlds of politics and personal friendships.

On Wednesday, Obama parted ways with adviser Jim Johnson, one day after shrugging off Republican criticism of the man who had led his search for a running mate. Republican aides denounced Johnson steadily after a weekend Wall Street Journal article cited loans he had received on favourable terms from a company embroiled in the nation’s mortgage crisis.

Obama ignored them on Monday, and largely dismissed them on Tuesday. Johnson, who had conducted similar searches for previous Democratic presidential candidates, was an unpaid volunteer with a “discrete task”, Obama said.

“I am not vetting my V.P. search committee for their mortgages,” he said a bit huffily.

Less than 24 hours later, as aides to Republican presidential candidate John McCain hammered away, Johnson stepped down. It was his choice, said Johnson, a former chairman of mortgage lender Fannie Mae, although similar claims are sometimes made when advisers are shoved aside.

Johnson marked something of a middle ground in terms of longevity after political attacks begin.

Foreign policy adviser Samantha Power left Obama’s campaign almost immediately after a Scottish newspaper reported that she had called Hillary Rodham Clinton then Obama’s top rival – “a monster”.

Obama’s ties to Power were not as strong as those he had with the Rev. Jeremiah Wright, his longtime former pastor and friend.

As Obama and Clinton fought for the nomination, news outlets and websites repeatedly aired video clips of sermons in which Wright cursed America and accused the government of conspiring against blacks.

As pressure built on Obama to distance himself, he gave a highly publicised speech on race in March. Obama said Wright had erred, but that “I can no more disown him than I can disown my white grandmother”.

Six weeks later, Obama broke it off after Wright went before TV cameras at the National Press Club and restated some of his most incendiary views.

When a visiting minister later ridiculed Hillary Clinton from the pulpit Wright had occupied for two decades, Obama took the final step and left his longtime church, Trinity United Church of Christ in Chicago.

All political leaders struggle with such decisions. President George W. Bush infuriated many fellow Republicans by keeping Donald H. Rumsfeld as defence secretary long after the Iraq war had proven more deadly and politically unpopular than the administration imagined.

Obama’s campaign declined to discuss details of his decisions regarding Johnson or other advisers.

But his supporters are quick to note that McCain has suffered his share of personnel embarrassments. At least five aides have left his campaign after criticism of their links to lobbying and special interests.

Hillary has had staffing headaches, too.

Bill Shaheen, a co-chairman of her national and New Hampshire campaigns, had to apologise and step down after he said Obama’s admitted use of drugs as a teenager could be used against him if he becomes the Democratic nominee.

At least one Obama adviser has proven that aides can re-emerge from the dog house.

Economist Austan Goolsbee reportedly had told Canadian officials earlier this year that Obama’s criticisms of the North American Free Trade Agreement were not as deeply felt as they appeared on the campaign trail.

Obama’s spokesman, Bill Burton, said at the time that Goolsbee was not representing the campaign when he visited Canada.

Not much was heard from Goolsbee for months. This week, he co-hosted a campaign conference call touting Obama’s economic proposals and criticizing McCain’s.—AP