In the course of his lengthy career, actor and director Clint Eastwood, now 94 years old, has created some enduring American cinematic archetypes: the taciturn poncho-clad Man With No Name of Sergio Leone’s trilogy of 1970s spaghetti westerns; the loose-cannon cop Harry Callahan who, in Sudden Impact (1983), delivers the immortal line: ‘Go ahead, make my day,’ which was quoted by President Ronald Reagan in a speech to Congress; the loner pioneer, such as The Preacher in Pale Rider (1985), who enacts justice himself in Western films which, as a cinematic genre, Eastwood has defined as ‘the last masculine variety’ of genres including romance and comedy, it is perhaps the theme of justice that looms largest in his body of work.

This is true of his new film, courtroom drama Juror 2, in which journalist and recovering alcoholic Justin Kemp is summoned for jury duty in a homicide case. This is bad timing, as Justin’s wife is about to give birth at the end of a high-risk pregnancy, and Justin attempts to be excused, but to no avail. The action then moves to the courtroom, where, as the details of the case are described, Justin gradually realises, with a disturbing shift of dramatic focus, that he is in fact the guilty party. In Sidney Lumet’s 1957 courtroom drama Twelve Angry Men, Henry Fonda was the holdout member of the jury trying to persuade 11 other men out of their belief in the guilt of the accused. Here, too, everything appears to point to the guilt of the defendant James Sythe (Gabriel Basso), who has a history of violence and was seen to strike and pursue his girlfriend Kendall Carter (the director’s daughter Francesca Eastwood) before she was found dead, having apparently been beaten and thrown off a bridge. Prosecutor Faith Killebrew (Toni Collette), who is running for District Attorney (on the slogan ‘Faith for the People’), hopes to attract voters by securing a conviction in a high-profile domestic violence case and is sure of the outcome. And here, too, a holdout juror – in this case Justin – believes in the defendant’s innocence for the very good reason, which he is understandably reluctant to disclose, that he may himself have been responsible for the young woman’s death.

Juror 2 does not attempt the carefully maintained moral ambiguity of a more recent example of courtroom drama, French director Justine Triet’s Anatomy of a Fall, a film where, even after the credits have rolled, viewers are still left to make up their own mind about what really happened to the victim. In Eastwood’s world there is a greater sense of reliability. We trust the version of events that arises out of a series of flashbacks to the night of the crime. Yet there certainly is a discernible moral twilight zone in the story, and it is contained within the figure of Justin himself.

As Justin, who, when recounting his recovery from addiction to the other members of the jury, mentions in passing the dangerous ability of alcoholics to ‘charm anybody’, Nicholas Hoult brings to the part the ambivalence of his early part as the manipulative Tony Stonem in the teenage TV drama Skins. Hoult has also been cast in a forthcoming retelling of Nosferatu as the tormented Thomas Hutter: he looks at home in a nocturnal Gothic reality.

Darkness looms large in Juror 2, both without and within the character of Justin. Alternating with daytime scenes set either outdoors or in the courtroom, bathed in shades of Indian-summer sun, the nocturnal scenes are, for the main part, flashbacks to the night of Kendall Carter’s death. The initial flashback, when we see the neon sign for the fateful roadside bar Rowdy’s Hideaway turn from monochrome to red as the scene changes to colour, is at once enchanting and ominous because it is a familiar trope of film noir, an American cinematic genre that flourished in the 1940s and 50s and inhabits a fallen universe of losers who struggle with their fate, lurching disastrously from bad decision to bad decision. Film noir is suffused with the ineluctability of tragedy transposed into an American context. Edward G. Ulmer’s Detour (1945) is an emblematic example of the genre, with its flashback narrative, roadside-diner setting, ill-fated encounters and anti-hero vainly struggling to avoid disaster. In Juror 2, when the scene of the crime is summoned out of the past and Justin, along with the other members of the jury, travels back to a few crucial moments before his own irretrievable act, the irony of his predicament is gradually revealed. It is precisely when trying, like Oedipus at the crossroads, to bypass what he fears may be his destiny – in his case the temptation of relapse – that Justin ends up a killer.

But as the story develops and as Justin, while simultaneously trying to shield himself and to save the defendant from a life sentence, is called upon to examine and probe himself, becoming his own juror (an effect of doubling suggested, perhaps none to subtly, by the title), he remains ambivalent even to himself. That is because Juror 2 may belong, rather than to the straightforward category of forensic courtroom drama, to another genre, that of a dyed-in-the-wool morality tale of intense American hue.

The 19th-century American writer Nathaniel Hawthorne, author of The Scarlet Letter, also wrote some remarkable short stories set in the America of early Puritan settlers and reflecting, not without subtle criticism, their intense preoccupation with the idea of original sin and the claims of law and conscience. Most relevant to Juror 2 might be Roger Malvin’s Burial (1832), a tale of obsessive guilt inspired by a true story. After being caught up in a skirmish with Native Americans, the settler Roger Malvin lies wounded in the wilderness and encourages his companion Reuben Bourne to leave him to die near a landmark rock and return to bury him later. Bourne goes home and, out of obscure motives, tells Malvin’s daughter that he has made sure to bury her father. He later marries her and lives on with increasing guilt ‘like a serpent, gnawing into his heart’ blighting him, making him a haunted man. Years later, while Bourne and his teenage son are out deer hunting in the wilderness, Bourne finds his steps guided inexorably towards the landmark stone where Malvin was left to die unburied. Later, hearing some moving object in the undergrowth, Bourne fires, shooting his own son. Thus he expiates his sin.

The narrative of Juror 2 is similarly implacable. The screenplay, by Jonathan A. Abrams, is remarkable in its spareness, the film by its restraint. There is something pleasingly minimalist about Eastwood’s avoidance of any more than strictly necessary backstory for the characters. One effect of this is to make the characters whom Justin meets on his path – a retired detective, an AA sponsor, a youth worker and fellow juror who says to Justin, in an obscure moment of clarity: ‘I see you’ – as near-allegorical figures of justice. One telling detail is the final scene of the film, which was shot in three different versions. In the first one, Justin opened the door to find Faith standing outside, flanked by police officers; in the second version, there was a police car behind her; in the third version, which was retained for the film, she stands alone, simply as the incarnation of justice, which she earlier defined as ‘truth in action’. Juror 2 has the disquieting limpidity of a Puritan morality tale.