You could replace line 32 with:
$WAFV_Errors .= WAValidateRQ((($_POST["Country"] == "US")?$_POST["State"]:"n/a") . "",true,7);
and line 42 with:
$WAFV_Errors .= WAValidateRQ((($_POST["Country_2"] == "US")?$_POST["State_2"]:"n/a") . "",true,16);
Then it would only validate the State if the country was set to "US"