I am a 30 year customer of NBD->Bank One->Chase with a number of rather substantial accounts. Recently wrote my Chase account a large check on a Chicago bank. The other bank site shows the check was paid the next day. Chase refuses to make the funds available. Says it will hold the check for 9 days. 1. Can they do this, even though they already were paid? 2. what recourse do I really have if they hold it 20 days or 200 days? It seems impractical to sue Chase, and the current Comptroller of the Currency is a Republican appointee

Chase probably has a standard policy on dealing with third party checks. There may be a standard number of days used to hold checks depending on the amount. However, they still need to pay you interest from the date of deposit.

I would challenge them to show you where the 9 days is written into their procedures.

Yes, merely "clearing" your bank, does not mean it is clear of the system.

This is a protection of several bank schemes moving money from bank to bank.

Also sadly there are 1000's of internet scams using checks mailed to people

This is really done for your protection and the banks protection.

Banks normally have a written policy on deposits of large checks and the holding period. I have seen some up to 15 days depending on size of check

yes, merely "clearing" your bank, does not mean it is clear of the system.

This is a protection of several bank schemes moving money from bank to bank.

Also sadly there are 1000's of internet scams using checks mailed to people

This is really done for your protection and the banks protection.

Banks normally have a written policy on deposits of large checks and the holding period. I have seen some up to 15 days depending on size of check

I don't mean to be overly negative but: I am well known to my bank branch, and have several pieces of ID. I showed them a check image from the other bank confirming it had been paid. They could easily have called the other bank to further confirm that it had been paid. Under these circumstances I fail to see how waiting another 8 days , or 800 days, would change anything.
However it turned out to be very costly for me, as a proposed investment got considerably more expensive during the wait. Now, I would not deny Chase the right to operate as they choose so long as I am not as a taxpayer supporting them, (and without that support, namely the taxpayer guarantee of FDIC, and the "too big to fail" doctrine, they could not exist.) Does no one take offense at these shenanigans by the banks?