In the past two months, the Houthi rebel group has seized a cargo ship, attacked several other commercial vessels and fired at least half a dozen missiles hundreds of kilometres from its base in western Yemen. In the past nine years since it emerged from northern Yemen and mounted a violent takeover of Sanaa, the Yemeni capital, the group has carried out more than 1,000 attacks against infrastructure important to the global economy – most of it oil facilities and airports in Saudi Arabia. The Houthis may control less than half of Yemen’s territory, but their aggression leaves an outsized footprint on the world stage.

The latest instance occurred in the Red Sea early on Sunday morning, when Houthi militants mounted an attack against a container vessel operated by Danish shipping giant Maersk. They were repelled by two US naval helicopters, which had responded to a distress call from the vessel’s security team. The resulting battle saw the choppers sink three Houthi ships, killing 10 militants.

Later that day, UK Defence Secretary Grant Shapps said his government would not hesitate to take “direct action” against the group – a phrase widely interpreted to mean London is considering air strikes on Yemeni soil.

By attacking ships and launching missiles, the Houthis claim to be helping to defend innocent Palestinians against Israel, which undertook a deadly ground campaign in the Palestinian enclave of Gaza in October. Given that the attacks have not only failed to move the dial in favour of Palestinians, but have in fact added to the number of innocent civilians in the region put at risk, the claim is at best dangerously naïve and at worst threatening a regional war without an end in sight. If the militants’ actions draw western powers into a new battlefront, ongoing peace talks in Yemen could unravel, injecting deep uncertainty into the country’s future – and risking even the Houthis’ own position.

The failure of the international community to end the onslaught on Gaza, largely due to full American support of Israel’s tactics, has only emboldened the Houthis further. And while the Houthis' own tactics may often appear strategically senseless, these are not rebels without a cause. Seizing control of Yemen is only part of the picture; the group’s objectives are expansive and pernicious. As a core member of the Iran-led, so-called “axis of resistance” that aims to remake the Middle East in a more extremist image, the Houthis are part of a transnational agenda.

Diplomatic efforts over the past two years to bring an end to Yemen’s conflict and establish an inclusive government were aimed, in part, at containing the influence of that agenda on the Arabian Peninsula and, eventually, releasing Yemen from its grip entirely so that all Yemenis – including those living in the Houthi stronghold areas – could prosper in peace. These efforts were going relatively well; Hans Grundberg, the UN’s Yemen envoy, spent much of last year shuttling between warring parties to build out an agreement. On December 23, he announced that both the rebels and the Yemeni government had committed to steps towards a ceasefire.

A conflagration in the Red Sea that raises shipping costs to Yemeni ports, brings western sanctions or reignites an international conflict would pull Yemenis back into their most desperate days. By gambling with their fellow citizens’ lives, the Houthis are gravely miscalculating. The challenge for the rest of the world is to respond strongly enough to show them this while avoiding its own miscalculations, too.