The Congressional Research Service caused a mild flap in the nation's capital when it disclosed that the country spent nearly $3.7 million last year supporting its four living ex-presidents and one presidential widow.

Ex-presidents receive an annual pension of $200,000, another $96,000 for staff, and the government picks up the cost of travel, office space, staff benefits and communications. The Secret Service protection that stays with them is covered under a separate budget.

Once this wasn't a problem. Presidents tended to be old and worn out when they left office. They didn't receive a pension until Harry Truman left office basically broke.

John Quincy Adams went back to the U.S. House, and William Howard Taft became chief justice of the Supreme Court, but the range of second careers is limited. Decorum prevents former presidents from opening restaurants, doing card shows or greeting casino customers.

Former Presidents Jimmy Carter and Bill Clinton support a range of good works through their foundations. When George W. Bush finishes his postpresidential chores — his library and his book — perhaps he will again take up the cause of public health in Africa, where he did great work during his presidency but got little recognition.

There are 12 presidential libraries, with Bush's soon to make 13. The law requires the ex-president to raise the money to build the library, then the National Archives takes over running it. The cost has been rising steadily. George W. Bush raised an estimated $500 million for his in Dallas.

Barack Obama will be a special case, because he will be relatively young — 55 — when he leaves office. Writing books and giving speeches is fine, and you can only play so much golf.

It seems that our ex-presidents are something of a wasted resource. We should ask more of them.