India's constitutional framework establishes a federal system, often described as a 'Union of States' (Article 1), characterized by a division of powers between the central and state governments, a written constitution, an independent judiciary, and bicameralism. However, in practice, the functioning of Indian federalism frequently exhibits strong unitary characteristics, leading many to describe it as 'quasi-federal' or 'federal in form, unitary in spirit'.

Several factors contribute to this unitary tilt:

1. Strong Central Government: The Union government possesses significant powers, particularly in legislative, administrative, and financial matters. The Union List contains more subjects of national importance, and in case of conflict, central laws prevail over state laws on subjects in the Concurrent List.
2. Emergency Provisions: Articles 352, 356, and 360 empower the President to declare national, state, or financial emergencies, respectively. During a state emergency (President's Rule under Article 356), the central government assumes direct control over state administration, effectively converting the federal structure into a unitary one. While its misuse has been curtailed by judicial pronouncements (e.g., S.R. Bommai case), the provision itself is a powerful centralizing tool.
3. Appointment of Governors: State governors are appointed by the President (on the advice of the central government) and act as representatives of the Union in the states. This position has often been controversial, with governors sometimes perceived as acting in the interests of the central government rather than impartially, especially when different parties are in power at the center and state.
4. Financial Dependence of States: States largely depend on the central government for financial resources. While the Finance Commission recommends devolution of taxes, states often rely on central grants-in-aid and centrally sponsored schemes, giving the Union significant leverage over state policies and priorities. The Goods and Services Tax (GST) Council, while a federal body, also centralizes significant indirect tax powers.
5. All-India Services: Services like the Indian Administrative Service (IAS) and Indian Police Service (IPS) are recruited and controlled by the Union government but serve in the states. This ensures uniformity in administration but also provides the center with a mechanism to influence state administration.
6. Integrated Judiciary: India has a single, integrated judicial system with the Supreme Court at the apex, followed by High Courts and subordinate courts. This integrated structure, along with the power of judicial review, ensures uniformity in law interpretation and enforcement across the country, but also means state judicial systems are not entirely independent of the central framework.
7. Parliament's Power to Reorganize States: Parliament can unilaterally form new states, alter boundaries, or change names of existing states (Article 3), demonstrating the Union's ultimate authority over the territorial integrity of states.

However, it is also important to acknowledge the evolving nature of Indian federalism. The rise of regional parties, the increasing assertiveness of states, the establishment of bodies like NITI Aayog (replacing the Planning Commission) to foster cooperative federalism, and the Supreme Court's role in upholding federal principles have introduced elements of cooperative and even competitive federalism. States are increasingly demanding greater autonomy and a larger share of resources.

In conclusion, while India's Constitution is federal, its operational dynamics often lean towards a unitary system due to the inherent centralizing features and the historical context of nation-building. Nevertheless, the federal spirit remains robust, with continuous negotiations and adjustments between the center and states, making Indian federalism a unique and dynamic system.