In the US, we have a Constitution that is a written document. While there are a lot of unwritten constitutional rules, the formal written text of the US Constitution sets the ground rules, by which everything is run. And in 2000, when there was some question about the result of the Presidential Election, this fact meant that everything was settled (even if it took some time) in a way that could not be contested.
Contrast Britain, which has a "constitution" that includes some Parliamentary laws (which can be changed, however, by simply passing another law, unlike our difficult amendment process!) but is mostly an accumulation of traditions. Right now they are trying to sort through the results of an election in which their House of Commons (which combines the role of a house of Congress here with that of the Electoral College) is without a majority.
According to one of those traditions, the sitting Prime Minister is given the first chance to try to "form a Government" (he has to put together a Cabinet and first have it approved by the House of Commons, unlike our system, where the Cabinet, though requiring Senate approval for each individual position, need not be in place for the President to take office).
On the other hand, there is the strongly-held belief that the leader of a party which has won the largest number of seats in the Commons, particularly if that party received the largest vote in a general election, should be given the first chance. And in this case, the incumbent Prime Minister, Gordon Brown, leads a Labour Party (that's how they spell it there), which has finished a rather distant second in seats (306 to 258), and was also far behind the Conservatives in votes. Furthermore, the third place (Liberal Democratic) party leader, Nicholas Clegg, is on record as agreeing with ths second proposition, that the leader of a party which has won the largest number of seats in the Commons, as well as the largest vote in a general election, should be given the first chance. And Clegg's position is important, because the Conservatives can get a majority if they join with the Liberal Democrats. So both Gordon Brown and the Conservative leader, David Cameron, believe they deserve the first chance.
Well, the way it works now is that Cameron has sent emissaries to talk with Clegg's people, but Brown's resignation has not taken place. And in fact Brown is fulminating that he deserves a chance first. But in fact, the Labour and Liberal Democratic parties together do not have enough seats (Labour's 258 plus the Liberal Democrats' 57 make 315, and 326 are necessary) to make a majority. So even if Brown could convince Clegg to join him, he would still need support from some small minor party.
And further complications ensue because a lot of British Conservatives feel they should not make any concessions to the Liberal Democrats to make a majority, but should try to govern without a majority. British practice permits such a minority government, but only if enough small parties agree not to oppose the Prime Minister's party to prevent its defeat on a no-confidence vote. And the Liberal Democrats' size is such that this is the only party that could provide this non-opposition in sufficient numbers, and Clegg is not likely to agree to do it without concessions. So that solution is a non-starter.
Isn't it great to have a written Constitution?