Just a short observation as I wrap up this look at Haggai’s prophecies: God has authority over all human politics. That is the assertion made here by God Himself. It is true. God was telling a government official through His prophet that He was in control of both of heaven and earth. And no throne or kingdom was beyond His grasp.
The warning was meant to encourage the returned exiles that foreign nations would bring them national prosperity again. But this would be God’s doing and not strictly the result of human endeavor. God even says that military outcomes will result in Israel’s enemies destroying themselves. This would clearly leave God in control and worthy of worship. So don’t get any more wrapped up in politics than God is. It exists to exalt God as He gets the glory! Human power is nothing to Him.