This article discusses some of the earlier cases where the granting of a pardon has been stopped.
http://pardonpower.com/2008/12/on-revocation-of-pardons.html
In reading a little more about this, it seems absolutely clear that the president can not revoke a pardon (regardless of Ms. Clinton's foibles). The only issue is at what point in the process the pardon is actually granted. Assuming an unconditional pardon the possibilities are:
1. When it is announced.
2. When the president issues the order for somebody to execute the pardon.
3. When the designated individual executes the pardon.
4. When the pardon is delivered.
In the Toussie case, the pardon was announced and the President seems to have signed a warrant that ordered the execution of a pardon for Toussie and others. But the pardon was not executed or delivered.
The only legal precedent seems to be that pardons aren't in effect until they are delivered. But current legal thinking is that they are in effect when they are executed, maybe because dead people often receive pardons these days. I think executed means signed by the presidentially authorized individual.
There are arguments, that Toussie's lawyers will no doubt make, that the presidential pardons are in effect when they are announced or when the president orders that they be executed. My guess is that Toussie's lawyers are going to charge a lot of money making that case but in the end Toussie will still be unpardoned and his parents will have spent a lot of money on expensive lawyers that accomplish nothing. And of course the 28K or so the parents gave to the RNC for greasing the process and the money they've give to various lawyers along the way to gain special access will be gone also. Their money might have been better spent if they used it to get the Israeli leadership to request the pardon. That seemed to be the bit that helped Marc Rich the most.
And on the Marc Rich pardon subject, the internet discussions on this topic often include the idea that Rove is behind the Toussie pardon reversal because he's trying to undermine the Eric Holder appointment for AG because of the Marc Rich Pardon and this pardon would weaken Rove's case. Pick your conspiracy theory and take your chances.
