They were the words we knew had been coming all along. "Rick, do it."

That was all the urging Rick needed to pull out the pistol Deanna had tried to ban and, at her command, execute Pete, the wife-basher who had just slit the throat of Deanna's peace-and-light architect husband Reg.

And with that, the Second Amendment triumphed over wishy-washy liberalism and The Walking Dead lurched unmistakably to the right.

Not that it hasn't done so before, and not to say that it will stay there, for above all else The Walking Dead is an arena in which competing political philosophies do gladiatorial combat - not to the death so much as "until next time".

And with the finale drawing a record audience of 15.8 million viewers in the United States, and with catch-up viewers topping the 20 million mark, there are likely to be a lot of next times.

Since Rick's band stumbled upon the walled haven of Alexandria, its resident ruler Deanna (Tovah Feldshuh) has been the voice of political reason, a measured if somewhat autocratic leader of the demos. The people will speak, the people will decide, the people will kick Rick (Andrew Lincoln) and his cohort out if they collectively agree that their vigilante ways are a threat to the harmony of their solar-powered, grey-water-recycling oasis of calm.

Until they need them, that is.

It was always going to come to this. The good folk of Alexandria had stayed safe, sheltered, secluded behind their wall - erected under the direction of Reg (Steve Coulter) - and that allowed them to cling to the belief that they really were good. Never mind their practice of abandoning their fellows to the walkers in moments of crisis, or taking those who don't fit in out into the wilderness and leaving them to fend for themselves, without weapons. They were good. The fact they had bake-offs and parties and nice houses made it so.

The true test of their virtue only came at the end of this episode, when that wall was breached and when Pete (Corey Brill) turned on one of his own.

Is this the al Qaeda phase of The Walking Dead, in which the smug balloon of US liberal's self-congratulation is violently punctured by an outside threat that may also have its echo within? Maybe.

Just before Pete's murderous moment, Rick had walked into the town meeting, his face splattered with the blood and gore of a walker whose head he had just exploded (no, it wasn't pretty).

"It got inside on its own," he told the town meeting, which until that moment had been a model of polite civil discourse. "They always will - the dead and the living. Because we're in here. And the ones out there, they'll hunt us, they'll find us, they'll try to use us. They'll try to kill us. But we'll kill them. We'll survive. I'll show you how."

Rick had them now, but he almost lost them again when he admitted he'd considered killing one of them, maybe more, to make his point. "But I'm not going to do that," he added, a little too late to calm the frazzled nerves. "You're going to change. You're not ready, but you have to be. Right now, you have to be. Luck runs out."

Which is where Pete staggered in, blade in hand (Michonne's katana, presumably), to tell them that Rick was "not one of us". But after that throat-slitting he was. Never mind that any jury would likely have judged it involuntary manslaughter rather than murder, desperate times demand desperate measures.

But just how desperate do they need to be? That's the question that continually gnaws at the heart of this show.

It's the question gnawing at the heart of Morgan Jones (Lennie James) too. He's been quietly stalking Rick all season, and finally he's found him. You could tell he's been clinging to the idea that Rick is some kind of saviour; it's there in the words on the map he's carrying, even though it was Abraham who wrote them, back at the church. "The new world's gonna need Rick Grimes."

Is it, though? And if it does, is that any kind of world to live in?

They're the questions that flickered over Morgan's face as he stood looking at Rick, gore on head, gun in hand, Pete dead at his feet.

There's got to be a better way than this, surely.

On twitter: @karlkwin