President Bush is preparing an exit strategy
The US President-elect, Barack Obama, has visited the White House with his family at the invitation of outgoing President George W Bush.
Mr Obama and wife Michelle were shown round personally by Mr Bush and the First Lady, Laura Bush. The Republican incumbent, whose policies Mr Obama frequently criticised on the campaign trail, has appeared keen to smooth the transition to power for his Democratic successor.
But it hasn't always been like this. Here is a look at some of the trickier transitions.
2000: IN George W Bush (R) OUT Bill Clinton (D)
Mr Bush looked awkward and uncomfortable as he sat next to Bill Clinton on his first visit to the White House as president-elect after eventually winning the 2000 election.
The reasons why were never fully explained - after all, Mr Bush was no stranger to the place, his own father having worked there as vice-president before serving one term in the top job as Mr Clinton's predecessor.
Some saw clues to his discomfort on the campaign trail, where Mr Bush had pledged to clean up the office of president - sullied, as he saw it, by Mr Clinton's dalliance with Monica Lewinsky in the Oval Office.
Others focused on the bitterly-disputed election result, in which Al Gore, Mr Clinton's vice-president, was finally denied the White House by a Supreme Court ruling after weeks of wrangling.
That process delayed Mr Bush's invitation to the White House and added an air of tension to the entire transition, with famous stories of Clinton staffers leaving "surprises" for their successors in the West Wing.
1980: IN Ronald Reagan (R) OUT Jimmy Carter (D)
There was little love lost between these two men, and it showed in a tense and largely unsuccessful White House meeting.
The 1980 Reagan-Carter meeting did not go well
Ronald Reagan, who had berated Jimmy Carter throughout the campaign as a disastrous president, appeared in no mood to listen to advice from a man he thought had steered the ship particularly badly during his time in office.
Mr Carter, on the other hand, was a one-term president rejected by the electorate amid troubles abroad and a failing economy at home.
Outgoing Vice-President Walter Mondale, who has described the first White House meeting as the "psychological transfer of power", observed that neither man enjoyed their day. "It all went over Reagan's head and Carter was really shaken," he later said.
1968: IN Richard Nixon (R) OUT Lyndon Johnson (D)
Despite having served only one full term, Lyndon Johnson decided not to seek re-election in 1968 amid disastrous news from the war in Vietnam and ongoing civil strife at home.
In his memoirs, Richard Nixon said their political and personal differences "melted away" when the Republican visited the White House after beating rival Hubert Humphrey to the presidency.
"As we stood together in the Oval Office, he welcomed me into a club of very exclusive membership, and he made a promise to adhere to the cardinal rule of that membership: stand behind those who succeed you," Mr Nixon said.
1960: IN John F Kennedy (D) OUT Dwight Eisenhower (R)
The 1960 election saw John F Kennedy take the reins - a Democrat who, at 43, was four years younger than Barack Obama when he won the presidency.
Outgoing President Dwight Eisenhower, an ageing Republican with a distinguished war record, was openly dismissive of the "young whippersnapper", the Associated Press says, deriding Kennedy as a "young genius" ahead of their meeting.
But he found himself genuinely impressed by his successor during their three hours together, praising his understanding of global issues and the "keenness of his mind" when the pair emerged from talks.
1952: IN Dwight Eisenhower (R) OUT Harry Truman (D)
Another frosty handover, as the departing Harry Truman - the leader who authorised the dropping of the atomic bombs on Japan and took the US into the Korean War - dismissed the political nous of his successor, a wartime hero and household name.
Mr Truman was disappointed that General Eisenhower had refused to condemn the tactics of communist-denouncer Joe McCarthy, accusing his one-time friend of betraying "almost everything I thought he stood for".
The planned White House meeting never took place, and, somewhat unsurprisingly, relations remained tense right up until inauguration day.
1932: IN Franklin Roosevelt (D) OUT Herbert Hoover (R)
The Depression-era handover from Herbert Hoover's discredited Republican administration to the energetic Democrat Franklin Roosevelt (FDR) heralded the beginning of the New Deal and comparisons have been drawn with the current situation.
But there were key differences: while the two men in 1932 neither liked nor trusted each other, Time magazine notes, Mr Bush and Mr Obama have not traded personal insults during the campaign - despite Mr Obama regularly criticising the outgoing president on policy.
While Mr Bush is widely lampooned by Democratic voters and supporters of John McCain attacked Mr Obama's personality during the 2008 contest, in 1932 the leaders themselves got involved.
Hoover called Roosevelt "a chameleon on plaid", accusing him of changing his political colours to suit the public mood, while FDR preferred the image of Hoover as "a fat, timid capon", Time reports.