A key premise in Marbury v Madison is that the Supreme Court’s jurisdiction is clearly defined by the Constitution, and therefore a legislative act that redistributes the jurisdiction must be unconstitutional:
In the distribution of this power, it is declared, that "the supreme court shall have original jurisdiction in all cases affecting ambassadors, other public ministers and consuls, and those in which a state shall be a party. In all other cases, the supreme court shall have appellate jurisdiction."...
If it had been intended to leave it in the discretion of the legislature to apportion the judicial power between the supreme and inferior courts according to the will of that body, it would certainly have been useless to have proceeded further than to have defined the judicial power, and the tribunals in which it should be vested. The subsequent part of the section is mere surplusage, is entirely without meaning, if such is to be the construction. If congress remains at liberty to give this court appellate jurisdiction, where the constitution has declared their jurisdiction shall be original; and original jurisdiction where the constitution has declared it shall be appellate; the distribution of jurisdiction, made in the constitution, is form without substance.
However, there seems to be a very significant elision here. The very next words in the cited section of the Constitution are:
both as to law and fact, with such exceptions, and under such regulations as the Congress shall make.
How can the court claim that the legislature cannot change the parameters of the court’s jurisdiction when the cited clause in the Constitution explicitly states that Congress has the authority to regulate it?