Peter Enns offers what he calls The Best Way of Getting out of the Whole Canaanite Genocide Thing, and It Comes Right from the Bible, but You may not Like it. I'll quote the core of his argument:
In Exodus 23, it looks like a pestilence of some sort (famine?
locusts?) by God’s hand is what will drive out the Canaanites: it will
throw them into confusion and so they will turn their backs on the
Israelites. This process, we are told, will happen gradually. But note
there is no word of annihilating the Canaanites by war.
In Leviticus, we see another side to all this. Note the use of the
past tense in these passages. Even though these words from God are
spoken on Mt. Sinai, i.e., before Israel entered Canaan 40 years later,
the expulsion of the inhabitants of Canaan is something God did. The Canaanites are vomited out of the land already.
These passages present an alternate view on how the Canaanites were
ousted from the land (expulsion, either already or in the future) than
what we find on Deuteronomy and Joshua (annihilation). The Bible carries with it multiple traditions of how the Israelites came into the land. (see also Numbers 33:50-56, which speaks only of “displacing” the Canaanites, not annihilating them).
Note, too, that the gradual displacement of the Canaanites in Exodus
23 coheres somewhat with the picture given in Judges as opposed to the
rapid Blitzkrieg victory tour depicted in Joshua 7-12 (e.g., Joshua
11:23, “So Joshua took the whole land, according to all that
the Lord had spoken to Moses; and Joshua gave it for an inheritance to
Israel according to their tribal allotments. And the land had rest from
On the one hand, this is good news if you want to think of Israel’s
settlement of Canaan in biblical terms that also takes the edge of [sic] the
violence. On the other hand, this is bad news if you want to follow the
Bible, since the Bible explains how the Canaanites ceased living in
their land in two mutually exclusive ways–i.e., the Bible does not speak
with “one voice,” which I know for some is more troubling than the
thought of God killing off a population.
You can’t have everything.