Last week we mentioned John McCain's struggling campaign.  Yesterday, his campaign was thrown into turmoil, as the majority of the top tier of his staff left the campaign.  The campaign director, Terry Nelson; the finance director, Mary Kate Johnson; and strategy chief John Weaver, along with their deputies.

Whether they jumped or were pushed depends on who you talk to, but what is not in doubt is that this is another blow to a campaign teetering on the brink.  The political futures market - probably the most reliable indicator of a candidate's likelihood to win the nomination - now prices a contract which will pay $100 if McCain wins the nomination at under $7 - compared to $34 for Fred Thompson (who hasn't even entered the race) and $36 for Rudy Giuliani - and around half the price of a month ago.

McCain lacks the money to compete across all the primary states. Most analysts think he will need to do better than expected in the Iowa caucuses to have any hope.  The problem for McCain is that this is a state in which he is unpopular and did not even bother to compete in when he ran for president in 2000.  Secondly, because the Iowa contests are caucuses rather than primaries, they demand massive organisational capacity.  It is far from clear that McCain will be able to fund this kind of operation.

All in all, things aren't looking good for Senator McCain.