Does assigning zero damage to a creature with deathtouch still count as lethal damage?

Deathtouch is a static ability that states any amount of damage a source with deathtouch deals to a creature is enough to destroy it (CR 702.2b). The key word is deals — damage must actually be assigned and dealt for deathtouch to apply.

When a creature with deathtouch is blocking or being blocked by multiple creatures, the attacking or blocking player must still assign at least 1 damage to each creature before moving excess damage elsewhere (CR 510.1c). This minimum-1 rule exists precisely because zero damage would never be lethal on its own, even with deathtouch.

CR 510.1d clarifies that a creature with deathtouch is considered to have 'lethal damage' assigned to it once it has been assigned at least 1 damage from a deathtouch source. Zero damage does not meet that threshold — lethal damage requires at least 1 point to be assigned.

Concrete example: You attack with a 1/1 deathtouch creature. Your opponent blocks with two 2/2 creatures. You must assign at least 1 damage to the first blocker (which is lethal thanks to deathtouch) before you can assign the remaining 0 damage to the second blocker — but that 0 damage does nothing and the second 2/2 survives.

So while deathtouch makes even 1 damage lethal, it cannot make 0 damage lethal. You cannot circumvent the minimum-1 assignment rule by claiming deathtouch makes zero damage sufficient.