There are few phrases as fundamental to US politics as foreign policy. It shapes the balance of power between branches of government. It separates a special class of public servants. And it commands sober respect from both sides of the partisan aisle.

Indeed, in American politics, “foreign policy” is a phrase used so unthinkingly that it may be strange to point out what it really is: a paradigm first developed to protect the English monarchy, imported across the Atlantic by our nation’s founders, stretched to breaking point by over two centuries of geopolitical change, and broken – at last – by the presidency of Donald Trump.

According to the old paradigm of foreign policy, there is a clear line between domestic and foreign: inside our borders, we may fight about taxes, transfers and fundamental rights; but once we venture outside those borders, it is our “national interest” against the world. In the immortal words of Senator Arthur Vandenberg: “Politics stops at the water’s edge.”

The concept of “foreign policy” emerged in 18th-century England as a strategy to insulate the Crown’s authority abroad from parliamentary pressure at home. “We ought not to pry into such secrets as relate to foreign affairs,” implored Sir William Yonge of his fellow Members of Parliament in 1743. “As our business relates chiefly to domestick affairs, we ought to keep within that province.” But in the US, foreign policy – and its notion of a national interest protected by the executive – became a cherished ideal behind which the founders promised to lead their city on the hill.

Trump has laid waste to this worldview. From welcoming Russian electoral interference in the US to seeking dirt on rivals in relations with China and Ukraine, Trump has eschewed the traditional rules of foreign policy to practice a novel form of foreign politics: a framework of international affairs with little regard for Vandenberg’s cardinal rule.

To the horror of the Beltway establishment, he leaves half the state department empty and elevates transactional horse-trading above institutional protocol. Rather than relying on career diplomats and respecting old alliances, he takes to Twitter and courts useful dictators. Rather than pretending to represent the national interest, he openly advocates for a narrow swath of supporters and cronies.

This is a paradigm shift long in formation. Over the course of the last two centuries, the Westphalian system that inspired the founding architects of US foreign policy – a world of sovereign nation-states communicating through their respective executives – has broken down, displaced by a new set of transnational networks often dominated by non-state actors: Facebooks and Googles, Blackrocks and Deutsche Banks.

Trump has eschewed the traditional rules of foreign policy to practice a novel form of foreign politics

In this new global context, the boundaries between foreign and domestic have blurred. China, for example, owns more US debt, trades more with the US, and emits more greenhouse gases than any other country. Unlike with past adversaries, the interests of countless American businesses cannot be disentangled from Chinese economic success.

The notion of a single “national interest”, for its part, has degraded to mere farce. After five decades of stagnant wages and inflamed wealth inequality, few believe that the boats still rise together. When the US government protects the intellectual property of its pharmaceutical companies – raising prices for American patients while guaranteeing offshore profits – whose interest does it really serve?

Trump’s election was a symptom of a foreign policy paradigm in terminal decline; his foreign politics a dark premonition of what might replace it. Not only were his supporters reacting to a general sense that they had lost control over their national borders in the process of rapid international integration; they were also reacting to a more acute sense that the US government and its army of diplomats merely channeled the interests of a transnational economic elite. Trump promised to attack that elite, and – through his diplomacy-by-Twitter – cut out the middlemen unworthy of trust.

Trump is, of course, not alone. From Benjamin Netanyahu to Vladimir Putin, rightwing leaders are practicing foreign politics to advance their personal interests, linking up in a network of like-minded authoritarians who have little respect for the cherished norms of the liberal international order.

Where does that leave the Democratic party and its presidential contenders?

Broadly divided into three camps: the Restorers, the Restrainers and the Transformers. Each takes a different view of foreign policy, though none faces up to the paradigm shift at hand.

Restorers like Joe Biden view Donald Trump as the great aberration who pushed US foreign policy off its stable path; their policies aim, therefore, to reset the clock: rejoin the Paris accords, re-sign the Iran deal. This is a platform of nostalgic denial: Restorers neither appreciate the fragility of Obama’s foreign policy victories, nor recognize his many failings.

The rules of the global game have changed for good. Trump and his allies see it clearly

Restrainers, by contrast, reckon with the failings of foreign policy past – in particular, a string of broken promises with respect to America’s armed intervention abroad. Their core commitment is to “end the endless war”, drastically downsizing the US military and demanding greater oversight of its operations. In other words, their aim is not necessarily to replace the old foreign policy toolkit wholesale, but to catch the arm of the US government as it reaches for its most lethal tool.

In this sense, the Restrainers ultimately defend the foreign policy paradigm, appealing to the more noble traditions of American diplomacy. But by calling for a more “responsible” form of statecraft, the Restrainers betray their own nostalgia for the calm waters of the liberal international order. The principle of restraint is certainly an important virtue in international affairs. But it is a brittle one: it implies that the US is holding back from serving its true interests, and is therefore vulnerable to strongmen who vow to break taboos and serve them better.

This is where the Transformers should come in. Represented in the presidential race by Bernie Sanders and Elizabeth Warren, the Transformers recognize the profound shift in international affairs and the range of new methods that will be necessary as a result.

Sanders speaks, for example, of the need for an “international progressive front” that supports “partnerships not just between governments, but between peoples”. Elizabeth Warren describes a similar seismic shift in our foreign affairs. “The world was changing before President Trump took office, and it will continue to change after he has gone,” Elizabeth Warren wrote in her pitch for a “Foreign Policy for All”.

But the Transformers, too, have offered little to move us beyond the old paradigm. Sanders provides few concrete plans to build a progressive front or international institutions to facilitate people-to-people partnerships. And Warren’s vision remains faithful to its core myth of a unified national interest. Her “foreign policy for all” is a contradiction in terms: protecting some American interests on the global stage will require undermining others.

Here, we can start to see the outline a different kind of a foreign politics: a progressive foreign politics, which begins from the same premise as Trump – that politics no longer stops at the water’s edge – but inverts its strategies, policies and priorities. One that builds new multilateral institutions, rather than wrecking them; one that powers democratic movements, rather than squashing them; one that is unafraid to champion the shared interests of a global 99% against those of a consolidated transnational oligarchy.

The rules of the global game have changed for good. Trump and his allies see it clearly. Democrats must now step up and confront their new reality. Politics no longer end at the water’s edge. But from watching these debates, Democrats seem like the last to know.