There’s something about Clive Lewis. Like it or not you can’t ignore him. The Labour MP for Norwich South was in almost every story about the Labour Party after he resigned from the Shadow Cabinet two weeks ago. And it wasn’t his resignation that was the focus for discussion, it was his potential as a future Labour leader. There was also a common tone in the coverage—an annoyance and cynicism, a grudging admiration that was mainly grudge.

What is it? Well, obviously, he is a man on the make. He wants the top job and his attempts to hide it haven’t been very convincing. His denial last weekend that he had leadership ambitions was a classic non-denial denial, straight from the Michael Heseltine playbook. And what’s wrong with ambition? Having it doesn’t guarantee success but not having any ensures failure. Politics is, of course, a profession defined by a will to power: every backbencher knows exactly how well they would fill any ministerial or shadow ministerial position. What makes Clive Lewis stand out is just how transparent his ambition is—and that leads to accusations of arrogance.

Which is all to the good. In the end, arrogance is the flip side of authority—and authority is the one characteristic above all of true leadership. And it is utterly lacking in Jeremy Corbyn, the current Labour leader. Indeed, it is no surprise that his campaigns chief, Simon Fletcher, quit last week.

Take the issue of Brexit, which was the trigger for Clive Lewis’s resignation from the Shadow Cabinet. Corbyn took a stand on this and issued a three line whip: the firmest possible instruction in the House of Commons. Faced with a revolt—and resignations from his Shadow Cabinet and front bench—Corbyn went into reverse. Labour MPs weren’t sacked or otherwise disciplined (and the whips have a panoply of punishments, from room allocation to bans on foreign trips), they simply got a stern warning to behave better in future. Now Corbyn, the serial rebel, was never going to make a convincing martinet, but if he was going to make the Brexit vote a conscience issue then why did he try to impose a three line whip? In the end, it is the Labour Leader’s utter lack of authority which undermines the ability of the Parliamentary Labour Party to be an opposition.

Which brings you back to Clive Lewis. The leadership question is clearly open in the Labour Party. Indeed, it has been since Corbyn was elected. What is different is that the issue is now being openly debated on the left which once solidly backed him. It was always inevitable that the left would split: it always has done. What was not so clear was what the fault line would be. In the end, it has been age. Older Momentum members neither need nor want a Labour government. They went to university when it was free. Have great final salary pensions. And bought their houses—which now have a massive capital value—in the 70s or 80s when prices were still low. In contrast, younger Momentum members have student debt, rarely have pension rights and can only dream of home ownership. Their problems need a political solution, so they are starting to care about electability.

Clive Lewis could see that last year. His conference speech as Shadow Defence Secretary was carefully calibrated. He admitted he was unpersuaded by the case for renewing Britain’s deterrent but said that he would support party policy on Trident—not least because it was popular with the public. Lewis might as well have said: “if you want a leader who is from the left but is electable then vote for me.” It was a smart move. So why does he arouse such anger?

The Twitter response to his resignation was revealing. A mixture of mockery, incredulity and plain anger. Talent rarely goes unpunished in the Labour Party but Lewis attracts levels of abuse that are reminiscent of Corbynites attacking Tony Blair.

And his first problem in the eyes of many of his colleagues is that he is talented. In Australia it’s called the “tall poppy syndrome”—the desire to drag down people who are successful. In the Commons it is not enough that you succeed as an MP, your enemies must fail too. In the end, though, leadership requires talent—and if Labour didn’t know that then the Corbyn leadership has been a long lesson in why it needs a combative leader who can speak well in public.

Secondly, he is lucky. The next Labour leader is most likely to come from the left: the new members who want a Labour government may be persuaded to abandon Corbyn but they will not abandon their beliefs. Just as it took a Neil Kinnock—from the left—to get Labour back on the march to power, it will take someone from the left to do the same now. It is hard for centrists but the Route One approach has been tried by Liz Kendall and Owen Smith. Now it is time for the soft left to take up its historic burden of making Labour confront reality.

Third, Lewis has chosen the defining issue of our age on which to make his stand. Brexit will make Britain poorer and no Labour MP came to office to make working people poorer. Yet far too many of them voted to invoke Article 50—the beginning of a process which will guarantee just that. As the reality of Brexit unfolds, taking the right stand on Article 50 will be seen for what it is: money in the bank.

Will he go all the way? That is to be seen. But as American writer Damon Runyon is meant to have said: “The race is not always to the swift, nor the battle to the strong, but that’s the way to bet.” In politics ambition isn’t everything, but it is nearly everything. Lewis has shown he has that. We will see if he has got the rest.