checking dates not working

[Marc Fromm <Marc.Fromm@xxxxxxx>]

I have this bit of code to see if a date is greater or equal to a set date.

echo(date("m/d/Y",strtotime($jobs_effective_start)));// displays entered date of 01/03/2012
echo(date("m/d/Y",strtotime(WSOFFBEGIN))); // displays set date of 09/16/2011

if (!(date("m/d/Y",strtotime($jobs_effective_start)) >=  date("m/d/Y",strtotime(WSOFFBEGIN)))) {
                $error.="The effective start date must be AFTER ".WSOFFBEGIN."\n"; unset($_POST["jobs_effective_start"]);
}

My error message is displaying. The if statement is executing as true, as if 01/03/2012 is not greater or equal to 09/16/2011.
This is not correct since a date in 2012 should be greater than a date in 2011.

If I use 12/31/2011 as the $job_effective_start date the error message is not displayed since 12/31/2011 is greater than 09/16/2011 and the if statement executes as fasle.

Any ideas on why a 2012 date is treated as not greater than a 2011 date?

Thanks

Marc