What was jehovah's response to habakkuk's question regarding why god would use a wicked nation to judge judah?

God was allowing conditions to get worse in Judah to show that because of their wickedness and disobedience to him would have consequences, they would not have his protection at the time. Jehovah's response was that the Chaldeans would be used to punish the nation of Judah. He reassures Habakkuk that the punishment " will not be late."  

Jeremiah 44:9  explains what Judah rulers were like, and just why Jehovah would allow the nation to be unprotected against the enemy nations.

protect u.s. businesses from competition

that was the type of government the spanish colonists were used to.