Perhaps, but this is complicated by the fact that MX or CA border agents are not under any obligation to even let you in their country, particularly without proof that you will be allowed to easily reenter the US (e.g. presenting a valid passport or passport card)

I asked a CBP officer about this recently and he seemed reluctant to endorse carrying only the GE card. His recommendation was "always carry a passport or passport card" when crossing a land border, though he did not say it was required.

Since CBP does not widely advertise the ability to use only the GE card at land borders. I am going to take the easy choice and bring the passport card with me.

But if I am already in MX/CA and lose my passport card, I can probably still use only my GE card to get back to the US.