A rule of all modern constitutions is that courts should remain apolitical. In reality, however, separation of powers is an ideal, not a fact. Trials should not be popularity contests, nor should elections be litigated – but this can be a hard separation to achieve. While Donald Trump argues that his prosecutors are making his case political and might even pardon himself if re-elected, he is not the only politician blurring the line between executive and judicial power. This situation would be recognisable to the ancient Greeks.

Ancient democracy recognised that the courts were part of politics, not above it. Although classical Greek cities had varying politics their constitutions tended to have a popular court, where everyone (who was a man and a free citizen) could take part in judging their fellow citizens. These cities were close-knit and highly politicised communities where the gap between poorer citizens and wealthy rulers was less significant than the gap between the citizens and their slaves. In such circumstances personal disputes could always have a political impact, and so political participation blended with participation in society more generally. Aristotle considered jury membership to be a defining fundamental feature of all citizenship. In democratic Athens the courts held a lot of power; jurors were paid and any citizen could enter the jury pool. Trials were understood as expressions of popular will, a vital channel through which citizens could express their political preferences. Politicians in Classical Greece were often on trial but they embraced the political quality of the courts.

A jury, as a randomly selected group of citizens, acted as a representative of the whole city. The formal oath of the Athenian jury shows an attempt at a depoliticised court system, including promises to ‘decide only on the matters in the charge’, and to ‘vote without favour or prejudice’. The content of court speeches tells a different story, however, and hearsay and reputation often dominate. The structure of Athenian trials made them an effective populist platform. No judge presided to decide what sort of evidence was admissible, and each case was a showdown between prosecution and defence, with both sides speaking for themselves (even if their speeches were sometimes written by a professional). Even sentencing was decided by the jury. This gave the jury total power in the court – and this could be used in political ways.

Athenian court speeches are preserved in collected works of orators such as Demosthenes (384-322 BC) and Isocrates (436-338 BC). It is not a coincidence that these men were also known for being politicians and speaking often in the assembly. Though trials were personal, political loyalties had a significant impact. Scrutiny in court was standard for all those entering and leaving public office, but politicians were also particularly popular targets for accusations of all kinds. Pericles (495-429 BC) faced multiple legal battles during his career as the leading politician of Athens. He, his family and his allies faced accusations of corruption, impiety and private immorality and special laws were passed targeting them. The historian Plutarch suspected that beyond this immediate impact on legislation, the ‘threatening and smouldering’ Peloponnesian War was ‘kindled into flame’ by Pericles; the war was an opportunity to evade his legal troubles. Facing similar troubles his cousin’s son, Alcibiades (450-404 BC), chose to defect from Athens to Sparta to avoid his own impiety trial. The courts had as many day-to-day political contests as the assembly, and they had a real political impact.

Cities that had been through a revolution would often put the previous rulers on trial. Eresos did this in 332 BC. The inscribed decree that convened the tyrants’ trial makes it clear this court was not meant to be independent of politics:

‘And a curse shall be made in the assembly at once that it may be well with one who judges and supports the city by a just vote, but for one who casts his vote contrary to justice the opposite of these things.’

The inscription also records an unsurprisingly guilty verdict:

‘It was judged. 883 voters. Of these, seven acquitted, but the rest condemned.’

Athenian juries were clearly politicised and populist, but even the politically conservative Spartans saw trials as a chance to address political grievances. The trial of a Spartan king was an established procedure and they were subject to increasing legal controls throughout the classical period. The Spartan Ephors, a body selected from among all Spartan men, had some legal oversight over the kings. In addition the Spartan general assembly, composed of all free Spartan men, had a key role in deciding issues of royal inheritance. The kings were under political pressure because of their vulnerability to these courts. King Leotychidas (c.545-c.469 BC) was caught red-handed taking a bribe and found guilty. He was banished from Sparta and his house was torn down. King Agis II (427-399 BC) was threatened under this law for simply not doing well enough in a war against Argos. He faced being fined and having his house destroyed. He was able to get a reprieve, but only by agreeing to allow the assembly to pass a law appointing ten Spartan officials to oversee his behaviour. Popular political will, even in very undemocratic Sparta, worked through the courts to constrain the power of a king even while in command on military campaigns. Juries represented a broader cross-section of citizenry than other institutions of power and so in non-democratic constitutions they represented populist opposition.

Alexander Hamilton called the judiciary the ‘least dangerous’ branch of government since it has no budget and commands no armies. The ancient Greeks teach us a different lesson; the courts can be a valuable but unstable avenue for popular feeling to have an impact on politics. If mechanisms of political accountability stop working, legal accountability can take its place. A defeat in court can ruin a politician in a way no electoral defeat can.

Timothy McConnell is a PhD candidate at the University of Leeds, specialising in ancient Greek political thought.