Special Provisions
If a State fails to comply with a valid Union executive direction, the President may hold that the State's government cannot be carried on in accordance with the Constitution.
This is a direct trigger connecting a state's failure to follow a lawful Union direction (like those under Articles 256-257) to the President's Rule mechanism under Article 356 - defying a valid central directive can itself become the specific justification for central intervention in that state's governance.
If a state government persistently refuses to comply with a valid Union direction (say, on protecting a nationally-important highway under Article 257), that non-compliance itself can become the President's stated ground for invoking President's Rule under Article 356.