Validating a date field to be in the future or today

I have a date field (not a date_time field). I setup an After Change rule to validate the field and give a "date must be in the future" message as needed. Originally, my rule was:

${entity.CENextStepsDate_c >= now()}

This works fine to verify that the date is in the future. But, now the users also want to be able to enter today's date. I thought the "greater than or equal" would have worked, but it does not. With the rule above, if they enter today's date, they still get the "date must be in the future" message. 

I tried changing the rule to be:

${entity.CENextStepsDate_c >= (now()-86400000)}

But, this gives an error "Expression entity.CENextStepsDate_c >= (now()-86400000) includes invalid characters." I tried without the parens and got the same message.

Any advice?