Article 72 Political Constitution of the United Mexican States

Every bill of law or decree, whose resolution is not exclusive of any of the Chambers, shall be discussed successively in both, observing the Law of the Congress and its respective regulations, on the form, intervals and manner of proceeding in the discussions and votings:

A.Once a bill is approved in the Chamber of its origin, it shall pass for its discussion to the other. If this one approves it, it shall be sent to the Executive, who, if he has no observations to make, shall publish it immediately.

B.Every bill not returned with observations to the Chamber of its origin within the thirty calendar days following its receipt shall be deemed approved by the Executive Power; once this term has expired the Executive shall have ten calendar days to promulgate and publish the law or decree. Once this second term has elapsed, the law or decree shall be considered promulgated and the President of the Chamber of origin shall order within the following ten calendar days its publication in the Official Gazette of the Federation (DOF), without endorsement being required. The terms referred to in this section shall not be interrupted if the Congress closes or suspends its sessions, in which case the return must be made to the Permanent Commission.

C.The bill of law or decree rejected in all or in part by the Executive shall be returned, with its observations, to the Chamber of its origin. It must be discussed again by this one,, (sic DOF 05-02-1917) and if it is confirmed by two thirds of the total number of votes, it shall pass again to the reviewing Chamber. If by this one it is sanctioned by the same majority, the bill shall be law or decree and shall return to the Executive for its promulgation.

The votings of law or decree shall be nominal.

D.If any bill of law or decree is rejected in its totality by the reviewing Chamber, it shall return to that of its origin with the observations that the former has made to it. If examined again it is approved by the absolute majority of the members present, it shall return to the Chamber that rejected it, which shall take it again into consideration, and if it approves it by the same majority, it shall pass to the Executive for the effects of section A; but if it rejects it, it may not be presented again in the same period of sessions.

E.If a bill of law or decree is rejected in part, or modified, or added to by the reviewing Chamber, the new discussion of the Chamber of its origin shall deal only with what was rejected or with the reforms or additions, without the approved articles being able to be altered in any manner. If the additions or reforms made by the reviewing Chamber are approved by the absolute majority of the votes present in the Chamber of its origin, the whole bill shall pass to the Executive, for the effects of section A. If the additions or reforms made by the reviewing Chamber are rejected by the majority of votes in the Chamber of its origin, they shall return to the former so that it takes into consideration the reasons of the latter, and if by absolute majority of votes present those additions or reforms are rejected in this second review, the bill, in what has been approved by both Chambers, shall pass to the Executive for the effects of section A. If the reviewing Chamber insists, by the absolute majority of votes present, on those additions or reforms, the whole bill shall not be presented again until the following period of sessions, unless both Chambers agree, by the absolute majority of their members present, that the law or decree be issued only with the approved articles, and that the added or reformed ones be reserved for their examination and voting in the following sessions.

F.In the interpretation, amendment or repeal of the laws or decrees, the same procedures established for their formation shall be observed.

G.Every bill of law or decree that is rejected in the Chamber of its origin may not be presented again in the sessions of the year.

H.The formation of the laws or decrees may begin indistinctly in either of the two Chambers, with the exception of the bills that deal with loans, contributions or taxes, or with the recruitment of troops, all of which must be discussed first in the Chamber of Deputies.

I.The initiatives of laws or decrees shall be discussed preferentially in the Chamber in which they are presented, unless a month elapses from when they are passed to the ruling Commission without it rendering a ruling, since in such case the same bill of law or decree may be presented and discussed in the other Chamber.

I (sic DOF 24-11-1923). The Executive of the Union may not make observations to the resolutions of the Congress or of any of the Chambers, when they exercise functions of electoral body or of jury, the same as when the Chamber of Deputies declares that one of the high officials of the Federation must be accused for official crimes.

Nor may it make them to the Decree of call to extraordinary sessions issued by the Permanent Commission.