One of the interesting aspects about this play is the way that Scotland as a Kingdom is definitely not shown to be isolated and untouched by the politics of other countries. Indeed, the involvement of other countries in Scotland is something that Shakespeare skillfully weaves into the plot of the play to describe the wider political backdrop that forms such an essential part of Macbeth.
Let us consider two aspects to support my claim. Firstly, note that in Act I scene 2, Macbeth and Banquo are defending Scotland from a force made up of the rebel Thane of Cawdor and the forces of the King of Norway. Note the following description of the battle:
But the Norweyan Lord, surveying vantage,
With furbish'd arms, and new supplies of men,
Began a fresh assault.
The political implications of this statement are clear. Scotland is a kingdom that has to be defended and it is seen as a prize to be taken by other forces and powers.
Also, in Act III scene 6, we are told of the political involvement of England in the plot of this tale, as Malcolm has sought sanctuary in England, and is supported by the King of England in his armed attack of Scotland to re-take his rightful crown:
The son of Duncan,
From whom this tyrant holds the due of birth,
Lives in the English court; and is receiv'd
Of the most pious Edward with such grace,
That the malevolence of fortune nothing
Takes from his high respect.
To a large extent, Malcolm's successful invasion of Scotland is only possible thanks to the support that King Edward of England gives him. Again and again, therefore, the wider political backdrop of this play is shown to be an essential part of the action.
The political influence in the play is the fact that the king at the time in the real world was King James I. He was a descendant of Banquo. In the play, Shakespeare creates the prophecy to show that Banquo's descendants will be king. Therefore, it shows that King James I is the rightful heir to the throne.
Government: King Duncan
War: the battle between scottish and norwegian forces in the beginning of the play