Claim. Pardoned officials can be brought to justice under U.S. law; specifically, they can be impeached and convicted, even post-term, and impeachment convictions nullify pardons. The second part of this claim is at odds with prevailing opinion in the legal community, so below are included the logical details of the nullification argument.
Post-term impeachment. The possibility of post-term impeachment has been covered here by Jon Ponder, who cites two sources:
* The Wikipedia's entry on "impeachment":
It is possible to impeach someone even after the accused has vacated their office in order to disqualify the person from future office or from certain emoluments of their prior office (such as a pension).
* Section 9 of A CITIZEN'S GUIDE TO IMPEACHMENT by Alan Hirsch, Esq.:
Does it sound farfetched for Congress to impeach and try someone who is no longer in office? It has happened! In 1876, Secretary of War General William Belknap [who served in the scandal-plagued Republican administration of Pres. Ulysses Grant], accused of accepting a bribe, resigned just hours before the House was scheduled to consider articles of impeachment. The House went ahead and unanimously impeached him, and by a vote of 37-29 the Senate rejected the argument that Belknap's resignation should abort the case. The Senate proceeded with the trial, but Belknap was narrowly acquitted. A number of the Senators who voted for acquittal explained that they felt they lacked jurisdiction because of his resignation...
[...]
Evidence suggests that the Framers of the Constitution concurred in this conclusion --- they did not regard resignation as automatically precluding impeachment or conviction.
Nullification of pardons: So far as I can tell, the notion that impeachment convictions nullify pardons was first noted by Citizen Spook, based on detailed parsing of two clauses of the U.S. Constitution. What follows is based on that work. It'll be helpful to keep the following points in mind while reading further:
(1) Presidents pardon offenses, not judgments, verdicts, or people.
(2) The distinction between ``may'' and ``shall'' is very important, and the framers of the Constitution understood that.
(3) Offenses alleged in cases of impeachment (aka impeachment allegations), whether convicted or acquitted, may subsequently be liable and subject to indictment, trial, judgment and punishment --- otherwise, they would in effect be pardoned, and the framers were adamant that the power of pardon belongs to the president alone.
Here is a refinement of Citizen Spook's nullification argument, but based on a single clause:
* Article 1, Section 3, Clause 7 (aka 1.3.7):
Judgment in cases of impeachment shall not extend further than to removal from office, and disqualification to hold and enjoy any office of honor, trust or profit under the United States: but the party convicted shall nevertheless be liable and subject to indictment, trial, judgment and punishment, according to law. [Emphasis added.]
Note that 1.3.7 is the framers' answer to: ``What happens when impeachment allegations result in conviction?'' It rules regarding impeachment-convicted offenses.
The nullification argument is a simple tautology. Since, by definition, pardoned offenses are not punishable, offenses for which a party is "liable and subject to ... punishment" are de facto unpardoned. So, by 1.3.7, any impeachment allegations that result in conviction (aka impeachment-convicted offenses) become unpardoned, i.e., any prior pardons of those offenses become null and void.
When, if ever, do impeachment-convicted offenses become pardonable? Clause 1.3.7 does not say how long impeachment-convicted offenses must remain unpardoned. On that question, there are competing views, each hinging on:
* Article 2, Section 2, Clause 1 (aka 2.2.1):
[The president] shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment. [Emphasis added.]
The key issue here is the meaning of 2.2.1's cases-of-impeachment exception. Here are the three major answers regarding the pardonability of impeachment-convicted offenses:
* Whenever. The prevailing view is that 2.2.1's cases-of-impeachment exception means that pardons have no effect on 1.3.7's removal-and-disqualification subclause and that ``shall'' means ``may'' in 1.3.7's second subclause, which makes it superfluous in view of note (3). The effect is that the president can grant non-nullifiable pardons for any offenses at any time, but pardons have no effect on the consequences of impeachment convictions.
Note, however, that 2.2.1's cases-of-impeachment exception explicitly disempowers it wrt impeachment allegations, including those resulting in conviction, which are therefore the exclusive province of 1.3.7, which in turn nullifies their prior pardons, if any.
* Post-judgment. The second view is that as soon as judgment is rendered in a case of impeachment, that case is no longer one of impeachment. So, by 2.2.1, following an impeachment conviction, the president can immediately issue pardons for the offenses cited in the conviction, even replacing pardons it nullified. Suppose, for example, that Bush pardons Cheney for some offense, and, sometime after the end of Bush's term, Congress impeaches and convicts Cheney, thereby nullifying that pardon. Under this view, Bush's successor(s) would be free to choose whether and when to grant Cheney a new pardon.
* Never. The third view (Citizen Spook's, pretty much) is that the president can pardon all offenses except impeachment-convicted ones, which consequently remain unpardoned and unpardonable forever.
In a case of impeachment, by definition, the case consists of the grounds for impeachment that get reviewed by the House: the allegations (alleged offenses), the facts in evidence, the relevant laws, and the arguments offered in support of those allegations, all of which persist beyond the judgment in the case. So the case persists forever, and its allegations retain their status as offenses alleged in a case of impeachment.
Clause .2.1 grants the president power to pardon all offenses against the United States, except impeachment allegations, which by 1.3.7 become unpardoned upon conviction, and nowhere does the Constitution restore presidents' pardon power over them. By omission, 1.3.7 leaves acquitted impeachment allegations pardonable in that it does not say: ``the party impeached shall be liable and subject to ... punishment.''
It is sometimes claimed that the cases-of-impeachment exception also prohibits the presidents from issuing pardons while under impeachment themselves, but that doesn't affect the considerations above.
Acknowledgement: the entire section on pardons was inspired by and derived from Citizen Spook's work --- link above.
UPDATE: Here is a very useful reference on post-term impreachment (PDF): http://afterdowningstreet.org/...