“Transporter Phasers” (from SFA “Vitus Reflux”)

[Christopher]

If that's what an old constitution class can do what can the Enterprise D or E do to a planet?

The D was not a warship, but a research vessel with defensive capability. Just because it was larger doesn't mean it would've had more powerful weapons. The E was a post-Borg design, though, so it was probably more geared toward combat.

Again, though, all you need to cause a mass extinction is one shuttlecraft at high impulse. Or a tractor beam to accelerate an asteroid onto an impact trajectory.

 

[Candleicious Ghost]

The D was not a warship, but a research vessel with defensive capability. Just because it was larger doesn't mean it would've had more powerful weapons. The E was a post-Borg design, though, so it was probably more geared toward combat.

Again, though, all you need to cause a mass extinction is one shuttlecraft at high impulse. Or a tractor beam to accelerate an asteroid onto an impact trajectory.

True enough... Tractor beam and fling a rock or two. Still General order 24 sounds like an order of last resort

 

[Christopher]

Still General order 24 sounds like an order of last resort

The idea that Starfleet would even have an "annihilate a whole planetary population" protocol has always been controversial. Many fans have wanted to assume Kirk was bluffing, except he can't have been, since all he said to Scotty was "General Order 24, two hours," and Scotty knew what he meant.

 

[Candleicious Ghost]

The idea that Starfleet would even have an "annihilate a whole planetary population" protocol has always been controversial. Many fans have wanted to assume Kirk was bluffing, except he can't have been, since all he said to Scotty was "General Order 24, two hours," and Scotty knew what he meant.

Indeed.. Well at least now I learnt of this bit in the episode which I don't think I have ever seen. I wonder if the Federation still has such an order on the books in Picard's time.

 

[Henoch]

The idea that Starfleet would even have an "annihilate a whole planetary population" protocol has always been controversial. Many fans have wanted to assume Kirk was bluffing, except he can't have been, since all he said to Scotty was "General Order 24, two hours," and Scotty knew what he meant.

Yes, I think the episode was clear; Kirk was not bluffing, but he was betting that the planetary leader(s) would capitulate.

At the open of the episode, the ship's mission and serious mood of the situation is established:

FOX: Captain, in the past twenty years, thousands of lives have been lost in this quadrant. Lives that could have been saved if the Federation had a treaty port here. We mean to have that port and I'm here to get it.
KIRK: By disregarding code seven-ten, you might well involve us in an interplanetary war.
FOX: I'm quite prepared to take that risk.
KIRK: You are. I'm thinking about this ship, my crew.
FOX: I have my orders, Captain, and now you have yours. You will proceed on course. Achieve orbit status and just leave the rest to me. You're well aware that my mission gives me the power of command. I now exercise it. You will proceed on course. That's a direct order.

and

Captain's log, stardate 3192.5. Now in standard orbit around planet Eminiar Seven. My orders are clear. We must establish diplomatic relations at all cost. Preparing to beam down to planet surface.

General Order 24 is a Federation policy to force capitulation of a hositle world to the Federation, or be destroyed. In A Taste of Armageddon, Kirk was betting that Anan would capitulate:

MCCOY: But you didn't know that it would work.
KIRK: No. It was a calculated risk. Still, the Eminians keep a very orderly society, and actual war is a very messy business. A very, very messy business. I had a feeling that they would do anything to avoid it, even talk peace.

 

[Christopher]

General Order 24 is a Federation policy to force capitulation of a hositle world to the Federation, or be destroyed.

If so, that makes it even worse, portraying the Federation like mobsters or imperialists threatening people into compliance. It's incompatible with the benevolence we've come to associate with the Federation. It shows how much the concepts were still in flux that early in the series. As I said, it's always been controversial in fandom.

 

[Ithekro]

In universe, that might be a side effect of "The Vulcan Hello" in how to deal with species like the Klingons that seemingly only respect power or combat or require warfare as part of their culture. After the disaster in 2256, one might think Starfleet would place in a general order that covers things like that, even if they hadn't followed Vulcan advice on that matter before.

 

[Christopher]

In universe, that might be a side effect of "The Vulcan Hello" in how to deal with species like the Klingons that seemingly only respect power or combat or require warfare as part of their culture. After the disaster in 2256, one might think Starfleet would place in a general order that covers things like that, even if they hadn't followed Vulcan advice on that matter before.

Well, that doesn't make sense. The "Vulcan hello" didn't mean actually destroying the people you wanted to negotiate with, which obviously would be self-defeating -- just a token baring of teeth to show you had the strength and courage to be worthy of respect. It's just a prelude to actual negotiation, proving your strength is on a par with the Klingons' so that they're willing to negotiate as equals. Forcing the other party to submit to your demands on pain of extermination is anything but an equal footing, so it's not remotely the same thing.