Narendra Modi, India’s prime minister, last week tore up the constitutional rules of self-government for Kashmir, the divided Himalayan region over which India and Pakistan have been to war three times since partition in 1947.

The world hardly blinked, even though it was Kashmir’s autonomous status that enabled the Muslim-majority region to join India after the subcontinent divided. Revoking it could reignite a 30-year-old separatist insurgency — and risk nuclear war in South Asia.

Two decades ago, when India and Pakistan, nuclear-armed after reciprocal bomb tests in 1998, fought a 10-week mountain war over Kashmir at Kargil and on the Siachen Glacier, Bill Clinton declared the region “the most dangerous place in the world today”.

The then US president turned Kashmir into a global issue. In March 2000, he journeyed to both countries to try to damp animosities as both sides were openly contemplating nuclear war — something that still came perilously close to happening in 2002.

Scroll forward to the presidency of Donald Trump and his administration’s wilful and erratic foreign policy. For Mr Modi’s Hindu supremacist Bharatiya Janata party, Indian sovereignty over Kashmir is a touchstone. It may be that he has moved now because he was spooked by Mr Trump’s offer to mediate on the issue (made in an almost throwaway remark at a meeting in Washington with Imran Khan, Pakistan’s prime minister, three weeks ago).

Mr Trump claimed Mr Modi had asked him to mediate on the Kashmir dispute. This claim, instantly denied by India, suggests either cavalier ignorance or total disregard for the facts. New Delhi’s longstanding and immovable position has been that the future of Kashmir can only be resolved in bilateral talks (or conflict) with Pakistan. It is Islamabad that has tried to internationalise the dispute. As the weaker party, that makes sense.

This balance of power on the subcontinent, so often tested in the Himalayas, is what makes Kashmir so incendiary — and so inappropriate a subject for Mr Trump’s off-the-cuff approach.

Ever since the US, Pakistan and Saudi Arabia used mujahideen fighters to evict the Soviet Union from Afghanistan in the 1980s, the Pakistani military has been addicted to asymmetric warfare. Over three decades, it has backed a total force of never more than 5,000 Kashmiri separatists and Pakistani jihadis, who have held down some 500,000 Indian troops and paramilitaries in the Valley of Kashmir. But by licensing Pakistani military intelligence to abet jihadi forces, in Afghanistan as well as Kashmir, the army has Talibanised Pakistan, growing jihadi power out of all proportion to radical Islamist roots in the country.

But when both sides went nuclear, Pakistan achieved a parity of power with India it could never achieve on the ground. This increased the attraction of jihadi proxies to Pakistan’s generals and spies; push the Kashmiri button and the Americans, terrified of the spectre of mullahs with nukes, should come running. Yet, as we have seen, this time they have not. The dangers are unchanged but the button does not work anymore.

Elsewhere, Mr Trump’s foreign policy has served to legitimise, if it does not actively greenlight, irredentism and land-grabs. His decision to recognise Jerusalem — including Israeli-occupied Arab East Jerusalem — as the capital of Israel, and to move the US embassy there, overrode international law and diplomatic consensus. This momentous move is almost certainly the prelude to the annexation of most of the West Bank, being pushed by Israeli prime minister, Benjamin Netanyahu, and his allies and rivals even further to the right. It signals the end of any possible two-state solution.

The idea of restraint is not the international order of the day: whether for Russia’s encroachment in eastern Ukraine; or Turkey in its drive against the US-backed Kurds in northern Syria; or even China in Xinjiang province with its intensifying crackdown on Turkic and Muslim Uighurs. This is not to mention the Chinese government’s threat to quell protests in Hong Kong and thereby end its autonomy. Why on earth wouldn’t Mr Modi choose this moment to annex Kashmir?

It may be that all these problems predate the advent of Mr Trump. But it is surely true that his administration’s contemptuous attitude to diplomacy, international law and treaties have only made them worse.

Mr Clinton’s remark 20 years ago may — if things go wrong — turn out still to be true. But with Mr Trump’s fondness for geopolitical arson, such as the tearing up of the 2015 nuclear deal Iran agreed with six world powers, the competition is a lot more fierce. – ft.com