We hope that Sen. Barack Obama (D-Ill.) has started a trend in disclosing all his earmark requests since he began his Senate career. The public deserves a flood of disclosure that, so far, is barely a trickle.

And we’re not talking just about earmark requests — which Obama’s presidential rival, Sen. Hillary Rodham Clinton (D-N.Y.), is not releasing — but tax returns for all three presidential candidates, Sen. John McCain’s (R-Ariz.) medical records, the donor list for Bill Clinton’s presidential library and archives on Sen. Clinton’s activities in the Clinton White House.

As we’ve noted before, House Democrats have vastly improved the transparency of the earmark process, requiring — for projects that make it into law — identification of sponsors, a statement of purpose and a certification that the Member has no financial interest in the project. The Senate is less transparent, requiring no project-by-project disclosure, just a no-conflict-of-interest statement.

Neither chamber requires disclosure of earmark requests. Last summer, Obama disclosed his 2008 requests, but not those for his first two years in the Senate. Last week, in the context of unsuccessful GOP efforts to force a moratorium on earmarks, he produced a full list and called on Clinton to do so as well. She should.

McCain is making his long crusade against earmarks a major campaign issue and forced Obama and Clinton to vote for the moratorium. Obama, meanwhile, is on a crusade against lobbyists. We think that both crusades are excessively purist. Some earmarks are worthy and lobbyists serve a vital purpose. But, in both cases, the public should know what is going on as fully as possible.

And full disclosure ought to apply to the finances of presidential candidates.

Obama has released his tax returns for 2006 only. McCain and Clinton have not released any. Under pressure, Clinton has pledged to release her 2007 return on or about April 15, but she is making no commitments about previous years. She could do it easily — and she should do it now.

The Clinton campaign has likened Obama to special prosecutor Ken Starr for requesting disclosure of the Clintons’ tax filings, donors to the Clinton library and archives of Sen. Clinton’s policy role as first lady. It’s a nonsense charge — and the fact that all of that is still hidden is a fit subject for criticism on the campaign trail.

The public has every right to know the sources of the Clintons’ income, who has given how much to the Clinton library and how much Sen. Clinton actually was involved in the White House decisions for which she is claiming significant experience.

And McCain, 71 years old and a melanoma survivor, needs to be as open with his medical records this year as he was in 2000, when he released 1,500 pages of records dating back to his naval service.

Is all this an invasion of somebody’s privacy? Sorry, presidential candidates aren’t private citizens. The rule has to be: Get It All Out.