Sen. Barack Obama bid an abrupt goodbye Wednesday to his vice-presidential search leader, James Johnson, when the aide stepped down after some unflattering news coverage. In a year when candidates are trying to be holier than thou, it's hard to see how the Washington insider could have stayed on.

Mr. Johnson, who also led Democratic Sen. John Kerry's search for a running mate in 2004, had been dogged by several issues. One involved his earning $21 million in 1998 as chief executive of Fannie Mae, which guarantees millions of mortgages. After Mr. Johnson left that year, federal regulators found that the government-sponsored organization had played with earnings to generate big bonuses for its executives.

Another report showed Mr. Johnson got three home mortgages worth a total of $2 million at better than prevailing rates. The mortgages came from Countrywide, the lender that has been rocked by the subprime lending crisis and that Mr. Johnson had many associations with as Fannie Mae's largest mortgage provider.

James Johnson has also served on corporate boards that were the focus of controversies over hefty executive compensation, a theme that Mr. Obama has hit hard during the campaign. It's easy to see how he was becoming a liability for the presumptive Democratic nominee.

The Obama aide's departure is only the latest to make news in the 2008 campaign. Both Sens. Hillary Clinton and John McCain jettisoned staff whose behavior undercut the campaign's message or gave the candidate a black eye with the voters.

What's unusual in Mr. Obama's case is he has purposely and strategically sought be a different kind of candidate -- one who rejects the old politics and the old Washington game. By setting a higher standard, for himself and for America, he can't afford to be tarnished by business-as-usual associates.

He was right to send James Johnson packing, but the best way for Mr. Obama -- and Mr. McCain -- to avoid such embarrassing exits is to not hire such aides in the first place.