Earth's naval policy without the Federation

If the Federation never formed, what would Earth's naval policy and geopolitics look like?

Earth would likely centralize, fortify the Solar System, and then expand outward under pressure from powers such as the Klingons, potentially resembling the Terran Empire structurally.

In this Star Trek counterfactual, Earth would have to develop governing and defence institutions without the Federation. The first military priority would probably be protecting the Solar System. Expansion could follow as Earth encountered enemies such as the Klingons. An alliance with the Vulcans would still leave the question of how much help Earth could rely on, and the resulting state might resemble the Terran Empire in structure.