Jeremy Corbyn is lauded by his supporters for his honesty and conviction. His repudiation of the shabby compromises and realpolitik of Westminster. With no less fervour, he is denounced by his opponents as an unreconstructed ideologue, a man allergic to compromise. But as the Labour leadership contest reaches its denouement, the frontrunner is showing his pragmatic side.

Having declared his support for British withdrawal from Nato ("I'd rather we weren't in it," he told the NS), Corbyn acknowledged at yesterday's Mirror hustings that there wasn't "an appetite as a whole for people to leave" and that he would instead call for the body to "restrict its role". The next Labour manifesto, should he oversee it, will not oppose membership (even the "longest suicide note in history" did not). Corbyn's compromise should not come as a surprise. Senior MPs told me that it would be all but impossible for him to find a shadow foreign secretary prepared to advocate withdrawal. On Tuesday, Andy Burnham, one of the few senior figures prepared to serve under the left-winger, had declared that he would resign rather than oppose membership. On this issue, Corbyn has shown that he is prepared to reach an accommodation with his colleagues and, more significantly, with the electorate - the act for which his rivals are condemned.

Nor is this the first time that Corbyn has put pragmatism before principle. After refusing to rule out supporting EU withdrawal, he later clarified that "We cannot be content with the state of the EU as it stands. But that does not mean walking away, but staying to fight together for a better Europe." On the monarchy, the lifelong republican ruled that abolition could wait because "my priority is social justice" (another dreaded compromise with the electorate). If, as seems certain, Corbyn is elected leader, more trade-offs will surely follow. Once principles have been conceded a few times for reasons of electability or practicality it is harder to avoid doing so again. Corbyn, it turns out, is a politician after all.