The idea that ex-presidents typically disappear to avoid conflict with the current office holder, is completely false. To the extent that it is true, it's because many presidents have been old, and sick after leaving office. Many die soon after. All the criticisms about Carter bucking precedent by being political, or Clinton's campaigning being inappropriate, are just excuses to criticize democrats.
The other reason is that 20th century republican ex-presidents have chosen to retire from view in their post-presidency. This could be for many reasons including laziness, or desire to earn corporate board money and speaking fees.
Lithium cola had a great front page entry on what Ex-Presidents' choose to do with their time after office. He pointed out that Jimmy Carter and Bill Clinton have done wonderful things, while recent Republican ex-presidents have chosen to do not much at all. He bets that W. will also choose the lazy selfish route.
Now I will Summarize what all the ex-presidents did with their time.
A main reason for the tradition of ex-presidents staying out of the limelight is that many were old and sick.
But many were active in politics. Several tried to regain the presidency or re-enter politics. Four of them ran in the general election, three as 3rd party candidates. Only Cleveland won. One became a U.S. congressman, one was elected a confederate congressman. One became senator. Taft became a Supreme Court Justice. Others considered runs for senate, or were considered for appointment in the senate. Too many to note were outspoken critics of their successors and future presidents, or advocated for or against a cause of interest.
Here are the presidents who survived their terms, excluding ex-presidents Clinton, Carter and Gore (whose long resumes we all know and love.)
Reagan has a good excuse for disappearing after 1988: Alzheimer's. He had to cover it up for a while so the media wouldn't ask if he had it during his second term.
Ford Survived 30 years. In that time he served on some government commissions, and councils and became an AEI fellow. Reagan considered him for VP. He founded a public policy institute.
Nixon traveled the world and represented the US at several international settings, and reported back to the president. He was an author and statesman. Lithium Cola stated that Nixon was the last republican president to have a productive post-presidency. Compared to Carter and Clinton, his 19 year resume is not totally impressive. You have to go back Taft or possibly Hoover to find a truly influential Republican ex-president.
LBJ was very unpopular and died 5 quiet years after leaving (If he had somehow been re-elected in 68 I bet the stress would have killed him in office)
Ike did little of note in his 8 years.
Like U.S. Grant, Truman was broke; he spent his years making a living. His integrity did not allow him to accept a corporate position like Republicans loved to accept. At the time, ex-presidents got no pension. Truman's Memoirs eventually gave him and Bess some comfort. Congress finally approved an overdue presidential pension.
Hoover was an ex-president for 32 years, dying in the LBJ presidency. He tried to win the GOP presidential nomination in 1936, but didn't come close. Hoover was outspokenly critical of the New Deal, and opposed US involvement in WW2-- he supported the Fortress America idea-- but he was massively unpopular and ignored throughout the depression. He did little until Truman asked him to tour Germany after WW2 and later appointed him to head a commission to re-organize executive depts. Ike did the same. He also oversaw the Hoover Institute at Stanford University and fundraised for the Boys Club. He also appeared at several Republican Conventions where he was honored each time (assuming he would die before the next).
Coolidge served on several boards and received a paycheck from New York Life Insurance company in his 4 years.
Wilson died after 3 years. He presided over the U.S. Historical society.
Taft became a Supreme court justice- in many ways the most accomplished ex-president. He preferred it to the presidency where he was considered a puppet. First of Teddy Roosevelt, then of the Republican Business powers.
Teddy Roosevelt went on Safari, collecting thousands of specimens for the Smithsonian. He then rebelled against the Republican party and his hand-picked successor and protege, Taft, who had neglected his progressive ideals for Republican capitalists. In 1912 TR lost the GOP primary, then ran as an independent "Bull Moose" in the general. He finished 2nd behind Dem. Wilson and ahead of Republican Taft. Afterward he was a writer, editor and advocated American involvement in WWI.
Cleveland was the only ex-president to become president. He lived 11 more years, was Trustee at Princeton and made his views known. He opposed Women's suffrage.
Benjamin Harrison lived 8 more years, wrote a book about the US gov't and worked as an Attorney.
Chester Arthur considered a run for U.S. Senate. He died less than 2 years after leaving office.
Hayes served on the Ohio State board of trustees.
Grant Toured the world with his own savings. He visited many world leaders and dignitaries, greatly enhancing the USA's world reputation. To provide for his family after his death, he wrote his memoirs while dying from throat cancer. They were a critical, popular, financial success.
Johnson was an accidental, ineffectual president. He had to do something afterward. I don't count him as a president. He later served as Senator of Tennessee, just as he did before the civil war.
Buchanan wrote a book, and died after 6 years.
Pierce lived 12.5 years and drank himself to death. He also gave his verbal support to the confederacy and opposed abolition.
Filmore lived 21 years. He served as chancellor at the U of Buffalo. He ran for president in 1856 in the Know-nothing party.
James K Polk died after 103 days.
John Tyler tried to prevent the civil war, then was a member of the confederate congress.
Van Buren ran for president as nominee of the Free Soil Party.
Andy Jackson was sickly his last 8 years.
John Q. Adams became a congressman.
James Monroe served on the Board of Visitors of the U of Virginia. Liberia named its capital city Monrovia after him.
Madison did little but go over his old papers, and served on a committee to re-write the Virginia state constitution.
Jefferson continued in public affairs, and most notably founded the University of Virginia-- the first great non-religious university in America. He was its architectural planner and its first president. It was also a model for America's State University systems.
John Adams retired to private life for 25 years. He died at 90, the second longest lived president behind Gerald Ford.
Washington was a farmer and distiller. He was appointed Lt General for any prospective war with France and was senior officer of the US Army and planned for a Provisional Army.