First, notice that out of the 12 tribes, only a part of the nation entered the battlefield after the death of Joshua. At first glance, that may seem harmless enough, but notice their succeeding steps away from achieving total victory over all of their enemies. Judah was selected "by God" to initiate the next phase of conquest... but then, Judah wanted someone else to help them do their job. Simeon agreed to do it because Judah made a deal with them to help them do theirs too. Again, there was nothing wrong in that per se, but it indicated a certain hesitancy and lack of faith. A crescendo of diversions was on the horizon. Next, Judah and Simeon didn't kill the king of their enemies... they only humiliated him. That's not what God had commanded (Exodus 23:23-33 & Numbers 33:51-56). Then, a fateful statement is found in Judges 1:19, they "could not drive out the inhabitants of the valley, because. They had chariots of iron." They couldn't!? What is that? What? Is God scared of iron chariots or something (Matthew 13:58)? Verse 19 began with the phrase, "The Lord was with Judah" - so, if they couldn't, it's because they wouldn't.
But, that's not the worst of it. Benjamin allowed Jebusites to remain in their city, Jerusalem. Ephraim allowed a Canaanite family of Bethel to live in exchange for the husband's cooperation and assistance. Then they allowed Canaanites to remain in Gezer. Manasseh didn't push the Canaanites out of 5 of their cities nor from the towns that surrounded them. Zebulon settled for receiving tribute payments from the inhabitants of their land. Asher actually shared neighborhoods with the Canaanites (Judges 1:32). Naphtali oppressed some of their enemies and befriended others. In Dan's case, the Amorites put THEM on the defense and forced THEM to flee. Other Jews were strong enough to force the Amorites to pay them tribute, but essentially the nation of Israel didn't do what they were empowered and commanded to do (Judges 1:28).