Sunday National reader George McQ. – who describes himself as “an American, British and Scottish citizen” – asks:

“It would be interesting to compare the strength and weakness of the American constitution. Unlike Britain, it gives the legislature strong powers and the President usually has to negotiate with it in order to carry out a legislative program. As school children, we were always taught about the system of “checks and balances”. However, in the past 10 years, with America becoming increasingly politically polarised, the weakness of the American system has become evident.”

We asked leading expert on constitutional matters Dr Mark McNaught of Rennes University to respond:

AS someone who was raised in the United States and holds a Doctorate in Political Science, I have developed a keen appreciation of both the strengths and the weaknesses of the US Constitution. While it has served as a coherent governing structure which has stood the test of time and is a source of unity, it has also shown its limits in the modern era in resolving issues the framers could not have envisaged.

The present US Constitution was written in 1787 after the Articles of Confederation, which had served as a Constitution since 1781, proved ineffective. Under the Articles, there was no executive or judiciary, so any laws passed by the Continental Congress were inapplicable, among other shortcomings.

Ratified in 1789, the present Constitution was remarkably innovative in overcoming the shortcomings of the Articles. It established the three branches of government: executive, legislature and judiciary, as well as “checks and balances” which enable each branch to limit the power of the others, preventing any one from accumulating too much power.

It also established the powers of the three branches. Most were granted to the Congress, with the president having relatively few. Over the intervening 230 years, the Constitution has both evolved and grown through constitutional amendment, law, and Supreme Court jurisprudence. The presidency grew in power, especially during the New Deal of the 1930s and the Great Society of the 1960s, when many executive regulatory agencies were created to better govern the economy and society.

However, amending the constitution is very difficult, and has become impossible in this era of intense political polarisation. It requires two-thirds of the House of Representatives and two-thirds of the Senate to vote for the amendment, and three-quarters of the state legislatures must adopt it for ratification. The constitution has been amended 27 times, 10 of which are the Bill of Rights adopted in 1791. This process tacks on amendments to the end of the constitution, rather than being able to modify the original text.

This inflexibility of the Constitution is both a source of its strengths and weaknesses.

The very fact that the US Constitution has lasted for 230 years demonstrates a remarkable resilience and endurance, which is in part because it is a minimalist document.

It establishes the basic mechanisms for passing laws, the powers of each branch and other functions, but is not overly prescriptive. This has allowed the government over the years to adapt to the constitution, rather than the other way around.

The US constitution also enjoys broad acceptance among the population, and is supported by people of varied political leanings for different reasons.

Along with the flag, it is one of the most venerable unifying symbols, in that living under the Constitution is one of the few things that all Americans share. Children learn about the Constitution from an early age and take mandatory government classes in high school to learn the basics of civic political participation. Some carry around a copy of the Constitution in their pocket. This attests to a broad consensus over the Constitution as an important unifying symbol.

The governing system created by the Constitution mitigates against radical change, which has led to a stability of policy. Unlike the UK system whereby the party with a majority in parliament controls the legislative and executive branch, in the US it is very rare that one party controls the House, Senate and Presidency at the same time, and it doesn’t last.

Between 1992-1994 under Bill Clinton and 2008-2010 under Barack Obama for Democrats, and 2016-2018 under Donald Trump for Republicans, the same party controlled both houses of Congress and the presidency. Therefore, mixed government is the norm, rather than the exception. Whether or not this is a good thing depends on your political perspective, but it has curbed the worst impulses of presidents, excluded radical measures from the agenda and led to a stability of policy.

Despite these positive attributes, because the text of the constitution is impossible to change, it is incapable of adapting to the modern world. This has resulted in it lacking the necessary democratic guard-rails to prevent the US from falling into profound dysfunction. “Achilles’ heels” of the US governing system include:

A corrupt campaign finance system, enabling corporations and wealthy individuals to buy elections and have their interests represented, rather than the population at large.

Voting rights have been undermined, and many have been deliberately disenfranchised.

Unimaginable levels of gun violence, underpinned by the 2nd amendment, resulting in some 40,000 deaths annually.

The Constitution is silent or inadequate to resolving these very real issues, which the framers could not have predicted in 1787. Were the Constitution more easily amendable, including changing the original text, it could be modified and updated to help resolve them and others.

These changes in themselves would not be sufficient to resolve them, but are necessary constitutional tools for policymakers to do so.

However, as long as the US maintains the current constitution, it will continue to be an object of reverence and unity.

This unique column welcomes questions from Sunday National readers. Keep them coming – and send your questions to us at letters@thenational.scot