@tcely

Since the appointments clause doesn't ask anything of the Senate, what leads you to believe inaction is not available?

Again, this is an Article II instruction to the president, but there is no parallel instruction telling the Senate to do anything, which I'd say leaves it up to them.

And that's setting aside the way this all fits naturally into the system of separation of powers, coequal branches and all of that.

It'd be strange to me to interpret the appointments clause as allowing the president to command the Senate to act, for many reasons, not the least because it doesn't say so.