In an ideal world for Ted Cruz, he would have won Super Tuesday and catapulted himself to a delegate lead that everyone else would have been unable to make up. No doubt, that was Plan A for Cruz. However, being an excellent contingency planner, Cruz has clearly always had in mind the Plan B of being the last candidate standing against Donald Trump and beating him at the convention.

Cruz is doing half of what what he needs to in order for Plan B to be successful. That half involves preventing Donald Trump from winning the nomination outright. Cruz has done everything right when it comes to that half. He’s kicked Trump’s butt in the delegate fight and successfully kept his head low enough to cause about a third of the party to coalesce around him. That is, very likely, enough to keep Trump from reaching 1,237 on the first ballot.

But the other half of that equation he hasn’t done so well – and that half involves convincing people to vote for him instead of just against Trump. Granted, he has a relatively long time to get that particular chore accomplished; after all, the convention isn’t for over three months now. But if Cruz thinks that he can walk into the convention with the second most delegates behind Trump and assume that he will walk away with the nomination at a contested convention, he is ignoring some of the vital dynamics of this race and showing an uncharacteristic lack of foresight.

One of those dynamics is that right now, an awful lot of people are voting for Ted Cruz solely as a vehicle for stopping Trump. They have no personal loyalty to Cruz at all, and many of them would leap at the first opportunity to stab him in the back or ditch him for a candidate more to their liking – but they are even more horrified by Trump. Remember that Cruz lingered persistently in the 15-20% range until virtually all the other candidates dropped out.

Many of the folks who will be at the convention – in particular the Rubio delegates and Kasich delegates, and the Trump delegates that he hasn’t successfully infiltrated – share this view that Cruz is almost as risky of a bet in the general election as Trump. If a halfway plausible reason to take the nomination away from both Trump and Cruz arises, they will jump at it. And some might well defect to Trump.

To allay these concerns, Cruz needs to show that he can actually take on Hillary, rather than just talk about being better suited to take on Hillary than Trump. To do this, he needs to prove that he can expand his potential base beyond people who are already persuaded that voting for Ted Cruz is the best idea that anyone has ever had. He has to show that he can do at least some of what Trump has done, which is to appeal to potentially disaffected Democrats. He has to speak to issues that are of concern to independent voters, beyond saying that Obamacare should be repealed and all Obama’s executive orders should be rolled back.

He needs to do more of speaking to concerns people have about situations like the water crisis in Flint. He has to discuss how a President Cruz would substantively handle problems that face everyday Americans better than the Obama administration has and better than President Clinton would. He has to launch attacks on Hillary that actually score in the media. These are all skills he will need in spades in the general, and he needs to display that he can manage them now.

I would like to think that the establishment would not be dumb enough to stab the supporters of both Trump and Cruz in the back, but they have done things that are dumber in their day. Some part of that is on them, but Cruz can go a long way towards making it happen by showing himself ready to take on Hillary in the general.