The good news for Rishi Sunak is that, as widely predicted, his Rwanda bill passed the Commons with relative ease. But in keeping with the curse faced by so many recent Conservative prime ministers, getting what he wants could be just the start of his troubles. There is one very important point to make first. However tricky things may get implementing the measure, if Sunak had become the first prime minister since 1977 to lose a bill on third reading it would have been disastrous, even politically terminal for him. So he will be pleased. This is, of course, is all relative. An authoritative prime minister in a strong position would not expect to see 60 MPs rebel to try to amend a flagship policy, as happened on Tuesday, let alone have to wait for the same MPs to largely back down to guarantee the bill’s progress the following day. As has been the case throughout the genesis of the Rwanda deportation scheme, one bequeathed to a reportedly sceptical Sunak by Boris Johnson, via Liz Truss, it is now hard to say whether he will face more problems being able to implement the scheme or having it blocked again. He could see the Lords try to derail the bill, or at least delay it, with the latter seen as the more likely option, even among potential rebels in the upper house. If it is passed, the unilateral declaration that Rwanda is a safe country to which asylum seekers can be deported will then almost certainly face a renewed judicial test. This route would allow Sunak and his ministers to hit out at “lefty lawyers” and “unelected peers” – but actual voters, already deeply sceptical of the Rwanda plan, might focus instead on the potentially broken promise to have the first planes leave by spring. And if the Lords does back down, and the bill proves legally watertight? That leaves Sunak having to enact a policy that could appear notably more inhumane once it involves real people who have fled real trauma, rather than a mass of unnamed “illegal migrants”. Most crucially, Sunak has bet almost all his remaining political credibility on a rush of flights to Rwanda having an immediate and noticeable impact on the flow of unofficial small boat crossings over the Channel, something few outsiders believe is realistic. Much as with Brexit, if this does not happen, Sunak and his critics on the right of the party are likely to insist that the idea was perfectly sound, just that it was not implemented with sufficient vigour or belief. Thus, even the third reading debate saw pre-emptive strikes from the likes of Suella Braverman, the former home secretary, who in an apparent repeat audition for the role of Sunak’s successor launched another attack on the European convention on human rights. The Rwanda plan, and particularly the way it has made small boats a near-totemic policy, has set off something of an arms race among Tory backbenchers, especially those who face a probable strong election challenge from Reform UK. In a contribution on his personal website published on Wednesday, Clacton MP Giles Watling argued for the entire matter to be passed to the military, with “British boots on the ground” in France. Watling, who is not known as a diehard on this issue, will have read recent polling which suggests Nigel Farage would win his Essex seat if he stood there. Every nudge towards the authoritarian, populist right on migration risks alienating the less noisy but arguably still more numerous contingent of centrist Tory MPs, who voted for the Rwanda bill but mainly while holding their noses. Among those to express their worries in the third reading debate was Jeremy Wright, the Conservative former attorney general, who has tabled amendments removing the idea that parliament can decide whether or not the UK is in compliance with international law. “Surely, if international law means anything, it must mean it does not lie in the hands of any individual nation state, even this one, to determine its own compliance with international law,” he said. Such thoughts might not be fashionable among Wright’s colleagues, but a reasonable number of more traditional Conservative voters take such ideas seriously. And much like the centrist MPs, at some point they will have had enough.