The President of India is the constitutional head of the executive of the Union, and all executive actions of the Government of India are formally taken in his name. His executive powers are vast and encompass various aspects of governance.

General Executive Powers of the President:

1. Head of the Union Executive: The executive power of the Union is vested in the President and is exercised by him either directly or through officers subordinate to him in accordance with the Constitution (Article 53).
2. Appointment Powers: The President appoints the Prime Minister and other Ministers (on the advice of the PM), the Attorney General, the Comptroller and Auditor General, the Chief Election Commissioner and other Election Commissioners, the Chairman and members of UPSC, Governors of States, Chief Justice and judges of the Supreme Court and High Courts, Ambassadors, and High Commissioners.
3. Administrative Powers: He makes rules for the more convenient transaction of the business of the Government of India and for the allocation among Ministers of the said business.
4. Supreme Commander of Armed Forces: The President is the Supreme Commander of the Defence Forces of India, exercising this power according to law.
5. Foreign Affairs: He appoints diplomatic representatives, receives foreign diplomats, and negotiates and ratifies international treaties and agreements (though these are subject to parliamentary approval).
6. Emergency Powers: The President can declare three types of emergencies: National Emergency (Article 352), State Emergency (President's Rule, Article 356), and Financial Emergency (Article 360).
7. Power to Issue Directions: The President can issue directions to states to ensure compliance with Union laws and policies.

Executive Powers when Two or More States are Involved in Non-Observance of an Inter-State Agreement: When states fail to observe inter-state agreements or comply with Union directions related to such agreements, the President's executive powers become particularly relevant, often through the Union government's intervention:

1. Article 365 (Failure to Comply with Union Directions): This is the most direct and potent power. If any State fails to comply with, or to give effect to, any directions given in the exercise of the executive power of the Union under any of the provisions of this Constitution, it shall be lawful for the President to hold that a situation has arisen in which the government of the State cannot be carried on in accordance with the provisions of this Constitution. This can lead to the imposition of President's Rule (Article 356) in that State. Directions could stem from inter-state agreements or national policies requiring state cooperation.

2. Article 263 (Inter-State Council): The President has the power to establish an Inter-State Council if it appears to him that the public interest would be served by its establishment. The Council's duties include:

   • Inquiring into and advising upon disputes which may have arisen between States.
   • Investigating and discussing subjects in which some or all of the States, or the Union and one or more of the States, have a common interest.
   • Making recommendations upon any such subject, and for the better coordination of policy and action with respect to that subject. This power allows the President to facilitate dialogue and resolution of inter-state issues, including non-observance of agreements, through a consultative mechanism.

3. Article 262 (Adjudication of Water Disputes): While Parliament makes laws for the adjudication of disputes relating to waters of inter-state rivers or river valleys, the President plays a role in the establishment of tribunals under such laws. For instance, the Inter-State River Water Disputes Act, 1956, empowers the Central Government (acting in the name of the President) to set up tribunals to adjudicate such disputes, ensuring compliance with their awards.

4. General Power to Issue Directions (Article 256 & 257): The executive power of every State shall be so exercised as to ensure compliance with the laws made by Parliament and any existing laws which apply in that State, and the executive power of the Union shall extend to the giving of such directions to a State as may appear to the Government of India to be necessary for that purpose (Article 256). Similarly, the Union can give directions to States in certain other matters (Article 257). Non-observance of inter-state agreements could fall under these provisions, leading to Union directions, and ultimately, potential action under Article 365.

In summary, while the President's role is largely formal, acting on the aid and advice of the Council of Ministers, his constitutional powers provide the framework for the Union government to intervene and ensure compliance, especially when inter-state agreements are not observed, ultimately upholding the federal structure and national interest.