As far as I'm aware, according to the theory of separation of powers, which is considered one of the foundations of democracy, prescribes the three government powers: executive, legislative, judiciary to be separated from each other and not wielded by the same person(s).

However, I can't shake off the feeling that in parliamentary democracies this is, in fact, fiction. Yes - there is a government that is theoretically separate from the parliament. However, in practice:

  • The political party (or coalition of parties) that has won the elections is usually the one that forms the government while at the same having the majority in the parliament. If this is not the case, a vote of no-confidence is usually soon passed.
  • Even more: members of such a party tend to accept the leadership of the leader of this party (duh) and, de facto not de jure, actually respond to this person. He can even subject members of his party to party discipline! And they will usually obey, because not doing so would often mean political suicide. Also, this actual leader will very often

As a result, if my observations are correct, this leader of the winning political party is, effectively, the one single man, who wields both powers: legislative and executive. As a result, there is no by-the-book separation of powers.

Am I failing to understand things correctly here?

  • 1
    The chief of state is part of the executive branch, isn't it? Otherwise, I tend to agree for countries where the government depends on parliamentary majority.
    – Alexei
    Mar 3, 2019 at 13:17
  • 3
    Are you asking about a specific country, or more generally? Some countries have constitutions that allow for such a separation, others do not.
    – Joe C
    Mar 3, 2019 at 13:58
  • When Judges are appointed by a political process is the Judiciary any different?
    – Jontia
    Mar 3, 2019 at 18:48
  • 3
    Your second assumption seems to be country-specific. In the system I am familiar with, leadership changes are quite common, even when they lead to changing the PM. Because the vast majority of party members are simply politically active citizens, party leaders have no power over them. Mar 4, 2019 at 2:57

3 Answers 3


This is, indeed, sometimes the case. For the example I understand, the United Kingdom, the very concept of separation of powers was introduced well after the constitution had begun to assume its modern form. There has never seemed to be a pressing need to reform the constitution on the basis of a theoretical principle, so it has not been done. Since a great many parliamentary democracies use the Westminster System, they tend to conform to the UK model.

In the Westminster System, the judiciary is strongly independent, but the legislative and executive functions are closely related and somewhat interdependent. However, the head of government doesn't get everything their own way, as is being demonstrated as present in the UK in the matter of leaving the EU.

  • 1
    Even the judiciary is somewhat weaker in the UK system, since Parliament can override any of their decisions with a simple majority vote, since there isn't a Constitution per se. Mar 3, 2019 at 15:58
  • 3
    @JonathanReez There is a constitution. It's just not one (amended) document
    – Caleth
    Mar 3, 2019 at 16:53
  • Until 2005, there actually was, as the question says, one single person in the U.K. who was part of the executive, the judiciary, and the legislature. it wasn't the Prime Minister. It was the Lord Chancellor. This is excluding the Crown, of course. (By the nature of a monarchy, there's one person at the top. It is what the word means.)
    – JdeBP
    Mar 4, 2019 at 17:29

Montesquieu's use of of the British constitution in De L'Esprit des Loix as an example of the separation of powers has been seen as somewhat ironic by constitutional scholars over the years for the very reason that you mention. The legislature and the executive are not really that separate, and the office of Lord Chancellor, outranking the Prime Minister, actually involved all three supposedly separate powers in one, as the Lord Chancellor presided over the upper house of the legislature, headed the judiciary, and was a politically-appointed (not elected) member of the Cabinet.

Here's what a Law Professor at Oxford Brookes had to say on the subject before the position was reformed:

[…] the position of Lord Chancellor is difficult to defend for a number of reasons. First, its cross-institutional nature does not accord with even the weakest doctrine of the separation of powers. The notion that a government minister should be head of the judiciary would seem to undermine, rather than protect, judicial independence.

— Diana Woodhouse (2001). The Office of Lord Chancellor. Hart Publishing. ISBN 9781841130217. p.12

She goes on to quote Professor Gavin Drewry from an article in 1992:

The "multiple rôle" of the Lord Chancellor has always entailed "a heroic piece of stagecraft, one which requires a massive suspension of disbelief on the part of the spectator".

— Diana Woodhouse (2001). The Office of Lord Chancellor. Hart Publishing. ISBN 9781841130217. p.13

And also, quoting Lord Mackay at the end:

Certainly any measurement of the instututional arrangements of British government would fall far short of the definitive version of the separation of powers. The law lords sit in the legislative chamber of the House of Lords and thus have a legislative function […] Much more significant is the fusion of the legislature and the executive, whereby ministers are members of both agencies and are involved in both functions, and the fact that functions, which can be most conveniently be labelled "judicial or legislative" are frequently carried out within government departments rather than by the courts. Such arrangements […] clearly diverge from "that antique and rickety chariot known as the separation of powers".

— Diana Woodhouse (2001). The Office of Lord Chancellor. Hart Publishing. ISBN 9781841130217. p.18

She goes on to highlight the legal fictions by which the monarch, the one person at the very top, is seen to be be three different people: the Crown-in-Parliament, the source of justice, and the person whose ministers form the executive. The U.K. is a monarchy, after all. It's what the "K" stands for.


[…] rather than supporting "our democratic institutions", the position of Lord Chancellor wold seem to break all the rules of a modern democracy. Not only is its occupant unelected and unaccountable to an elected body, but it would seem "undemocratic and monarchical for one person to exercise so much control over the judiciary".

— Diana Woodhouse (2001). The Office of Lord Chancellor. Hart Publishing. ISBN 9781841130217. p.22

There is a lot more on this there.

In reality, the separation of powers that you may be used to from countries where this is formally part of a written constitution, are not present in the unwritten U.K. constitution, which is quite messy, blurred, and overlapping. The Lord Chancellor was an extreme case, but there are others. The executive has strong control over the legislative agenda. The legislature permits a wide range of executive lawmaking through statutory instruments. The executive can (albeit that again this has been somewhat reformed) cause the legislature to be dissolved. And so forth.

Montesquieu influenced other countries, that adopted written constitutions afterwards, where one will see far stronger separations than what can be seen in the U.K.. The exemplar of separation of powers that he actually had available to him at the time does not compare particularly well, these centuries later. (There is, indeed, actually a school of constitutional thought in the U.K., certainly at least until the turn of the 21st century, that the separation of powers is not necessarily the best of ideas in the first place. This seems heretical to those who take it as axiomatic that separation of powers is a good thing, but it was seriously held by some U.K. constitutional experts.)

Of course, on the gripping hand, this is not "nearly always" by a long chalk. As mentioned, a fair number of post-Montesquieu constitutions exist which do embody this principle quite strongly. And even looking at Westminster systems alone, there is a spectrum.

  • 1
    Amazing that I've never heard of the Lord Chancellor before reading this answer. Mar 5, 2019 at 6:34
  • Thank you for your answer. Fun fact is I was basing my observations mainly on Poland (my country), not on UK - though I did (purposefuly) extrapolate them to all parliamentary democracies.
    – gaazkam
    Mar 5, 2019 at 17:45

To speak specifically to the separation of the judiciary:

This is a timely topic in Canada. As it stands today, in March 2019, the Attorney General of Canada is also the Minister of Justice. This is apparently causing some problems.

Indeed, the first Prime Minister of Canada served simultaneously as his own Attorney General.

  • 2
    AG and Minister of Justice are not judicial positions, though they may have some quasi-judicial powers in some countries, which can blur the boundary. Contrast that with, say, the former role of the Lord Chancellor in the UK, who was both a judge and a member of the executive (and a member of the legislature!). Mar 4, 2019 at 17:35
  • That's not a problem. A problem would be merging the office of Justice and Interior. Mar 4, 2019 at 18:35

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