select tag and fieldWithErrors

I've been trying to work out the rails way of handling this. I have my
form which contains:

<%= select(:user, :state_id, @states) %>

The only problem is that the fieldWithErrors div won't get added if
nothing is selected.

If I change it too:

<%= select(:user, :state, @states) %>

I get the error:

State expected, got String

Does rails have a graceful way of doing this?