It may be almost as rare as an appearance of Halley’s Comet. But when the stars are this aligned for a trade deal between the US and the EU, leaders should seize the moment.

For the past year, officials have been working on a potential transatlantic trade round – a process that would encompass more than half the world’s economy. The daunting list of sensitive items that bedevils trade between the two blocs has delayed the report by a few weeks. But the signs are that it is almost ready. President Barack Obama should give a final push so that he can include it in his State of the Union speech later this month.

There would be two lasting benefits to such a project – and a health warning on the negotiations. First, it would enable Washington and Brussels to set the terms for the rest of the global economy. There are plenty of trip wires hindering the free flow of goods and services across the Atlantic. But both blocs are fundamentally committed to the rule of law and democratic capitalism. By embarking on a project that would aim eventually to integrate their two market economies, the US and the EU would have the chance to set the template for countries such as China that take a sharply different approach to property rights. The pay-off would also be geopolitical.