A bench of Justices NV Ramana, Ashok Bhushan and Sanjiv Khanna said constitutional morality is different from political morality.
"In democracy, we can't curtail rights of political parties to align with other parties," the bench said.
The top court told the counsel appearing for Pramod Pandit Joshi of the Akhil Bharat Hindu Mahasabha, "Don't expect the court to go into arena of post-poll alliances in democracy and where it has no jurisdiction".
The Supreme Court said it is for the people to decide and not for the courts.
It observed that courts cannot issue directions to a party to implement its manifesto if it does not fulfil it on coming to power.