The Constitution, the Supreme Court, the Legislative Acts and the Executive approval of those Acts.
[#3Fan] The Constitution is easy enough to read...
It is obviously beyond your ability.
[#3Fan] ... and it says Congress can pass laws for states to prove their acts and their effect.
NO, it does NOT and has NEVER said that. It says "Congress may by general Laws prescribe the Manner in which such Acts, Records and Proceedings shall be proved, and the Effect thereof." The Constitution refers to Congress establishing the manner in which documents in the form of State Legislative Acts and State Judicial Records and Proceedings are to be authenticated for admission in court proceedings in other jurisdictions (states). The Constitution refers to the Congress establishing the legal effect of said authentication of said documents. The manner of said authentication has been established for ALL purposes since 1790. The Congressionally prescribed manner of said authentication is the same for ALL state Legislative Acts. The Congressionally prescribed manner of authentication is the same for ALL state Judicial Acts. The effect of said authentication has been established since 1790. It is currently codified at 28 USC 1738.
[#3Fan] Secession is an act ands falls under this of course.
Article 4, Section 1 of the Constitution is irrelevant unless the seceding state for some reason creates a legislative Act of Secession and there is a subsequent attempt to enter a copy of said State Legislative Act for use in the courts of another state. In that case, the document must be proved or authenticating by the officials of the State applying the official seal of the State to the submitted document. At that point the document is proved or authenticated as a genuine Act of the State Legislature and is deemed admissible for purposes of litigation.
[#3Fan] And whether the effect refers to the act or the laws makes no difference because the effect will be the same to any state.
Of course, the question is not whether the effect refers to the Act or the Laws, as you are well aware. As with the wording of the Constitution, you must change what was said in order to argue your inane position.
The manner and effect of authentication of documents (whether Legislative Acts, or Judicial Records or Proceedings) provided for under Article 4, Section 1 of the Constitition only establishes what must be done to have a document admitted in a court in another jurisdiction (state). Once authenticated (proved to be true documents) as prescribed by law, the effect is that such documents "shall have such faith and credit given to them in every court within the United States as they have by law or usage in the courts of the State from which they are taken."