The Constitution does not entitle members of Congress, or the houses of Congress, as such, to judicial relief for executive failure to carry out the law properly. Nor does the Constitution empower Congress to authorize lawsuits for that purpose by legislators or legislative bodies. The argument that the Constitution itself authorizes that kind of litigation rests on an error concerning the concept of legislative power. Insofar as it creates an interest that could be injured so as to figure in a cause of action, legislative power creates an interest in the validity of legal enactments, not in compliance with them. The interest in validity is not threatened when a private person fails to comply with, or when the executive fails to carry out, a valid enactment. Because the legislative power’s operation is complete when a valid enactment is created, to enable legislators or legislative bodies to sue executive officers for failure properly to carry out the law would be to enable them to exercise or control the executive power, and so would be inconsistent with the separate vesting of the two powers. Although the federal courts have generally assessed the constitutionality of lawsuits by legislators as such under the Supreme Court’s Article III standing doctrine, the genuinely important question involves causes of action, not the authority of the federal judiciary. Legislative lawsuits to enforce the law raise questions concerning the relationship between the legislature and the executive, not the role of the federal courts in the constitutional system.