For the record, acsenray’s strange theories of political science to one side, that person who acts in official capacity in behalf of the nation-state as a corporate entity, embodying it for purposes in which it needs to act with a single hand and voice, is the head of state. It can be a total figurehead sovereign (e.g., the King of Sweden no longer has any personal prerogative powers whatsoever), a president in a parliamentary republic (e.g., Italy), a president in a presidential republic (e.g., U.S.), the presiding officer of a real or figrehead multiperson body, such as Gosp. Kalenin, President of the Presidium of the Supreme Soviet during World War II, and thus the figurehead head of state of the U.S.S.R., even though Stalin was dictator. Heads of state embody the continuity of governance when individual governments can fall, as in a parliamentary vote of no confidence, they formally receive ambassadors in the name of the nation, they carry many formal functions (e.g., officially signing a bill into law). They may have no, a limited amount, a shared amount, or the overwhelming majority, of the power and authority for day-to-day governance, and the same spread of authority in crisis. Hitler, for example, received authority to rule by decree from Hindenburg in the latter’s capacity as head of state able to grant that authority in time of crisis – an example of when the power can be abused. Mr. Bush like all American Presidents has been head of state and head of government. In parliamentary republics, the premier is head of government, but a president with reserve powers functions as head of state.
Elizabeth II (but not the rest of the Windsors) is head of state for the U.K. – which is why it’s the United Kingdom, not the United Something-or-Other. She has very limited and circumscribed powers, plus a bunch of prerogative powers formally vested in her but to be exercised only on the “advice” (=instructions) of her ministers. The rest of the Royal Family function as backup to her, in the ceremonial duties expected of her (Can Her Majesty dedicate the new wing of the hospital? Well, no, but Princess Alexandra will be free; will she do?)
As for titles, the style of the late king’s (or kings’) consort(s) is completely up to the monarch regnant, who will normally take their wishes into account. AFAIK, “Queen Dowager” is not a formal style for “the late king’s widow” but has been used for clarification purposes.
In the U.K., there can be only one “His Majesty” alive – the king regnant. In historical contexts, of course, it’s appropriate to use it to reference former kings now dead. There can be a multiplicity of “Her Majesties” – the Queen Regnant, if the incumbent monarch is of the female persuasion, the Queen Consort, if the incumbent monarch is a married man, and any living former Queen Consorts.
As far as I know, “His Highness” with no “Royal” infixed exists in British stylings only as the title for visiting or resident-exiled foreign figures of royal or principial status.
“His (or Her) Royal Highness” includes, by a 1917 ruling of George V, only the following:
[ol][li]Children of the monarch[/li][li]Children of sons of the monarch[/li][li]The eldest living son of the son of the heir apparent[/li][indent][indent]to which may be added, as surviving from preceding reigns
[li]Brothers and sisters of the monarch[/li][li]Aunts and uncles of the monarch, on the royal side[/li][li]First cousins of the monarch, on the royal side[/li][li]Children of the monarch’s brother(s)[/ol][/li]
I’m not positive that’s all inclusive – it would need to include everyone who might have been entitled to “HRH” under a previous reign who could reasonably be expected to have survived.
