How is Congress' enforcement of Amendment 14 Section 3 of the Constitution not a Bill of Attainder?

Question

Background

According to this answer of Who enforces the insurrection rules in the 14th Amendment, section 3?, congress enforces Section 3 of the amendment just as it enforces all other sections of the Amendment.

However, Congress deeming any officeholder as outlined in that section as "having engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof" sounds like a Bill of Attainder, which is defined by Wikipedia below:

A bill of attainder (also known as an act of attainder or writ of attainder or bill of penalties) is an act of a legislature declaring a person, or a group of persons, guilty of some crime, and punishing them, often without a trial.

In effect, it would be the legislature stating that someone committed a crime (Insurrection, rebelling, or giving aid or comfort to enemies thereof), and then punishing them by revoking their right to hold office. While it may adhere to the U.S. constitution, it would seem to go against the idea of the legislature deeming someone guilty and rendering punishment without a Judicial trial. This cutting against the grain of the "spirit of the law" led me to ask:

Question

How is congress' enforcement of Section 3 of the 14th amendment not a Bill of Attainder?

Answer 1

It could be a bill of attainder if Congress purported to enforce it by passing a law that singled out an individual. But that's almost certainly not the intention of the phrase "shall have power to enforce, by appropriate legislation." Rather, it means that congress can make generalized laws for the purpose of enforcing any provision in the amendment.

But even if the amendment does mean to say that congress can pass laws singling out individuals under this provision, it doesn't matter whether that would constitute a bill of attainder a because the provision was enacted by amending the constitution. When an amendment conflicts with the original text or an earlier amendment, the later amendment prevails. That is inherent in the nature of amendments, especially in the context of the US constitution, where explicit repeal of earlier constitutional provisions is uncommon.

In general, qualifications for elective office are judged by some body or another, depending on the office. Any such body can find that a candidate falls under the ban in the 14th amendment, and that determination may in most cases be challenged in court. It is not necessary for congress to pass a law to make that happen. But congress could pass a law designating certain criminal offenses that would, if anyone were convicted of them who met the other criteria specified in the 14th amendment, trigger the ban. It is that sort of legislation that is enabled by the "appropriate legislation" clause.

Answer 2

While not a case about section 3 of the 14th Amendment, the Supreme Court has generally ruled what is and isn't a bill of attained, e.g. in Nixon v. GSA:

Appellant's characterization of the meaning of a bill of attainder obviously proves far too much. By arguing that an individual or defined group is attainted whenever he or it is compelled to bear burdens which the individual or group dislikes, appellant removes the anchor that ties the bill of attainder guarantee to realistic conceptions of classification and punishment. His view would cripple the very process of legislating, for any individual or group that is made the subject of adverse legislation can complain that the lawmakers could and should have defined the relevant affected class at a greater level of generality. Furthermore, every person or group made subject to legislation which he or it finds burdensome may subjectively feel, and can complain, that he or it is being subjected to unwarranted punishment. However expansive the prohibition against bills of attainder, it surely was not intended to serve as a variant of the equal protection doctrine, invalidating every Act of Congress or the States that legislatively burdens some persons or groups but not all other plausible individuals. In short, while the Bill of Attainder Clause serves as an important "bulwark against tyranny," it does not do so by limiting Congress to the choice of legislating for the universe, or legislating only benefits, or not legislating at all.

18 U.S. Code § 2383 in this case prohibits those convicted (largely on the same lines as section 3 of the 14th Amendment) from holding any federal office:

Whoever incites, sets on foot, assists, or engages in any rebellion or insurrection against the authority of the United States or the laws thereof, or gives aid or comfort thereto, shall be fined under this title or imprisoned not more than ten years, or both; and shall be incapable of holding any office under the United States.

As far as I know the constitutionality of 18 U.S. Code § 2383 has not been [con]tested directly in courts, but I see little reason why its constitutionality would fail court in view of Nixon v. GSA. See this law.SE answer for some cases where 18 USC 2383 was mentioned.

Answer 3

A writ of attainder criminalizes an individual or group of people. They are prohibited in the US because the Founders wanted our legal system to focus on crimes — specific acts committed by people contrary to law — and not on people whom one suspects 'might' commit crimes.

Section 3 of the 14th Amendment is not a writ of attainder because it is a penalty attached to a specific crime: the commission, aid, or abetment of insurrection against the United States. Insurrection is in some ways an unusual crime, since it is driven by partisan sentiment, not more personal reasons of profit or reward. But nonetheless, it is a specific act contrary to law, that act must be examined in a judicial or congressional trial before the penalty can be applied, and thus it falls well within the scope of the Constitution.

Answer 4

It is not a Bill of Attainder because it does not Congressionally establish criminal guilty or punishment. It would only establish a civil punishment, disqualification from holding office, without any possibility of a fine or incarceration. For example, as explained here:

A bill of attainder (also known as an act of attainder or writ of attainder or bill of penalties) is an act of a legislature declaring a person, or a group of persons, guilty of some crime, and punishing them, often without a trial. As with attainder resulting from the normal judicial process, the effect of such a bill is to nullify the targeted person's civil rights, most notably the right to own property (and thus pass it on to heirs), the right to a title of nobility, and, in at least the original usage, the right to life itself. Bills of attainder passed in Parliament by Henry VIII on 29 January 1542 resulted in the executions of a number of notable historical figures.

The use of these bills by Parliament eventually fell into disfavour due to the obvious potential for abuse and the violation of several legal principles, most importantly the right to due process, the precept that a law should address a particular form of behaviour rather than a specific individual or group, and the separation of powers.

There are arguments that it could be invalid on other grounds (e.g. denial of a right to due process in constitutionally protected legal rights to run for public office protected under the 5th and 14th Amendments), but that would be a ground distinct from disqualification of such an act of Congress as a Bill of Attainder.

Since it involves a civil penalty, rather than a criminal one, however, a bill passed by Congress could establish an administrative or civil court process to do so.