The US Department of State has fired two contractors and disciplined a third for accessing the passport file of presidential hopeful Barack Obama.
A spokesman for the department, Sean McCormack, said the cases were probably the result of "imprudent curiosity".
But he said it was not clear what the employees may have seen or what they were looking for.
A spokesman for Mr Obama suggested that the government could be using private information for "political purposes".
The BBC's North America editor, Justin Webb, says it is an extraordinary lapse in security which allowed temporary state department employees access to personal information on a man who is guarded by the secret service day and night .
8 January: New Hampshire primaries
Extraordinary indeed. Consider the timeline of the breaches:
9 January: First breach of Obama's records
19 February: Wisconsin primary and Hawai'i caucus (last day of Obama's February streak)
21 February: Second breach of Obama's records
12 March: Clinton campaign sends attack memo with the following text to reporters: "As voters evaluate you as a potential Commander-in-Chief, do you think it's legitimate for people to be concerned that you have traveled to only one NATO country, on a brief stopover trip in 2005, and have never traveled to Latin America?"
14 March: Jeremiah Wright's sermons capture nation's attention... and third breach of Obama's records.
Once is happenstance, twice is coincidence, three times is enemy action.
After the news broke Thursday that two employees of the State Department had been fired and a third disciplined for accessing passport records of Sen. Barack Obama, MSNBC noted a Clinton connection to the story. The network reported that Maura Harty, the State Department official in charge of the Bureau Of Consular Affairs during the first two breaches of Obama's passport, had served as an ambassador under Bill Clinton.
"That is one of the things we are obviously investigating," said Patrick F. Kennedy, head of bureau of consular affairs. "I have no reason to believe they did, but I am certainly not going to be dismissive of what is a serious and valid question. On the basis of fast work this afternoon [I don't believe they did]."
Patrick F. Kennedy? That's Patrick F. Kennedy, Assistant Secretary of State for the Clinton administration from 1993 to 2001. Also Chief of Staff for the Coalition Provisional Authority in Iraq.
This story is still developing. There might yet be a revelation that doesn't point right at the Clinton campaign. Watergate, anybody?