The situation is even worse in the UK where our executive branch is embedded in our legislature.
By definition here, the party in government enjoys a majority within parliament and for the last 11 years that majority has been very large.
In essence it means that unless the government wants to do something which is so appalling that even their own party can't bear it then they can do whatever they want.
Like the U.S. we operate a first past the post system with huge majorities being returned for nothing like an absolute majority of the vote and this tends to lead to see-saw politics as the country has to be so disgusted with the ruling party that they choose to exercise the nuclear option of clearing they and all their works from power.
The truth more often than not though is that many people who vote for a party are reasonably happy with some of what they've done and would have, at an earlier moment, exercised a vote showing their displeasure at a particular direction or measure had they thought that it could make a difference. With proportional representation that is an option. With first past the post, no such subtlety exists.
Many detractors of PR point out that it can lead to weak government which is really only yet another euphemism designed to imply that there's something awful about a government which actually has to compromise with competing interests in society to arrive at a result which is inherently more democratic.
For a country that was forced into a war it didn't want to take part in, has been forced to fund the development of an ID card system it doesn't need and has seen many traditional freedoms curtailed, I for one can't wait for 'weak' government.
