Declinism is the belief that a society or institution is tending towards decline, characterised by viewing the past more favourably and the present or future more negatively due to cognitive biases like rosy retrospection. Historically, this concept is traced to Edward Gibbon's History of the Decline and Fall of the Roman Empire, which posited a loss of civic virtue, and Oswald Spengler's The Decline of the West, which argued for inevitable cyclical civilisational collapse.The sources cover various aspects:

• American Declinism: It is often linked to economic stress and self-doubt stemming from foreign policy failures and domestic issues. Robert Bruner identifies geography, culture, productivity, institutions, and resilience as key factors in national rise and fall.
• British Declinism: This has been a recurrent, often politicised, theme interpreting relative economic decline as pathological societal failings, though historians often critique this as a distortion of reality.
• Declinism and Populism: Feelings of societal decline, particularly when political elites are blamed, strongly correlate with right-wing populist support, influencing perceptions of personal socio-economic vulnerability irrespective of actual status.
• Gendered Analysis: US declinism is underpinned by masculinism, using specific methodologies, privileging masculine values, and employing phallocentric imagery that equates US decline with feminisation and emasculation. This narrative can pave the way for figures like Donald Trump and a "hybrid masculinity" as a perceived solution.

Declinism, while it can serve as a warning to prompt action, also carries the risk of becoming a self-fulfilling prophecy or being exploited as a tactic by authoritarians.