An observance of certain forms had always been necessary for the legislative activity of the people to be regular and valid. In countries which recognise the sovereignty of parliament, the guardian of such forms is in the first instance the legislative chamber itself, in the second the courts of justice, which can, or should, be allowed to refuse to put into effect any law that has been passed in disregard of such formalities. This was the case at Rome. The laws themselves contained clauses which pronounced their ineffectiveness in case they should be found to violate the principles of the constitution, and the courts of justice had the courage to resist the enactments even of the provisional government of the dictator Sulla. But the executive authority might also have doubts about the propriety of putting into force a measure which it recognised to be irregular; and of this executive authority the Senate was the guide. Hence its well-established claim to point out a flaw in a legislative enactment, to establish the fact that the magistrate had questioned the people improperly, and that the answer of the people was therefore null and void. The exercise of this revising power once led to the greatest upheaval that Roman history records. It was by pointing out that the law of the younger Livius Drusus, which contained amongst its other clauses the gift of _civitas_ to the allies, was irregular as contravening the condition fixed by a _lex Caecilia Didia_ (98 B.C.) that wholly different enactments should not be contained in the same _rogatio_,[1335] that the Senate brought to a head the formidable conspiracy which culminated in the outbreak of the social war. History also brings to our notice the attempted reversal by this means of a popular judgment of a far smaller kind. It was suggested in the Senate that a notice of the alleged irregularities of Clodius’ _plebiscitum_ should be made the ground of Cicero’s recall; but the exiled orator, while thinking that there was “something in the notion,” yet preferred the far safer form of an abrogation of the enactment by the popular voice itself.[1336] When we turn from legislation to its complement of jurisdiction we find little direct interference by the Senate with the regular course of either civil or criminal procedure. On exceptional occasions it might decide the sphere of the praetor’s activity,[1337] and by its practical weight in the declaration of a _justitium_ it might suspend the operation of the business of the courts; but it did not interfere in the details of such business, and the appeals to the vetoing magistrates were left to their own discretion.