Everyone may know this already, but the difference between chiefs (heads) of state and heads of government wasn't always clear to me, so I'll give a brief tutorial (inspired by an article reporting on the visit of the Chinese Premier (who is the head of the Chinese government, but not the head of state)).
In America, the President is both the chief of state and the head of government, but in many countries the two offices are divided. In modern times, the main function of the head of state is to serve as a individual human representative for the nation as a whole, and the office is often non-political. Heads of government are administrators that wield government power and handle the management of the country. When most Americans think of things our President does as part of his job, we think of the duties of a head of government. In many countries the actual head of state has little real power, unless he is also the head of government.
In the UK, the head of state is the King or Queen, and the head of government is the Prime Minister. Technically, the Prime Minister is appointed by the monarch to administrate the country, but the monarch always appoints the head of the party who wins the most votes in the Parliamentary election. I'm told that this isn't a requirement, but no one really knows what would happen if the Queen decided to ignore an election and appoint someone of her own choosing.
France is somewhat of an anomaly; the head of state is a President who is elected to five-year terms (changed from seven years in 2001), and the head of government is the Prime Minister, who is nominated by the legislature and appointed by the President. The current President of France, Jacques Chirac, doesn't have a majority in the legislature, and thus is forced to appoint a Prime Minister from an opposition party. Since France's office of President has some political power of its own, this split between the head of state and the head of government leads to all sorts of complicated political power struggles.
Chiefs of state are always given much more elaborate treatment when they travel than heads of government are, even though they often have far less power. For instance, it's my understanding that when the Prime Minister of
England Britain visits America he's greeted by the Vice President, rather than the President himself (although he will obviously meet with the President later). The Premier of China is the head of the Chinese government, which makes it unusual that he's being received with as much pomp as is apparently the case.
President George W. Bush may have stripped down White House protocol in keeping with a time of "war" but Chinese Premier Wen Jiabao will get "spectacular" treatment Tuesday, complete with a 19-gun salute, an official said.
Wen will arrive at the presidential mansion for a South Lawn ceremony only offered during this administration to visiting heads of state, a senior administration official said.
Then he and Bush will hold talks in the Oval Office before sitting down to lunch.
Some observers have commented that Wen's reception will fall short of that accorded by the Clinton administration to the last Chinese premier to visit Washington, Zhu Rongji in April 1999.
Clinton and Zhu held a joint news conference, and appeared together at a sparkling White House black tie dinner similar to those held for heads of state, with an A-list of guests from politics, academia, the arts and entertainment. ...
A 19-gun salute will crack overhead, two blasts fewer than the 21-gun volley offered to heads of state, but much more than the average foreign head of government can expect at the White House.
Premier Wen won't be hosted by President Bush, but rather by Secretary Powell, which is more appropriate.