>our ideology (liberal democracy) is protected across the world

this is pure propaganda and is completely false statement, not grounded in reality. US has no problem protecting despotic autocracies like the Pinochet's junta in Chile or Saudi Arabian theocratic monarchy (a birthplace of islamic wahhabism).

The actual goal of military is to protect the status of USD as a global reserve currency and ensure all important nations are its vassals, fully subordinate to the US government.

The underlying reason is America is printing trillions of dollars out of thin air, not backed by anything, other than the threat from US military, so vassal states keep recycling their earned surplus currency into USD bonds and treasuries