Under what circumstances may the president send federal troops intoa state without approval from the State government

Martial Law

Explanation:

Martial Law may be declared by proclamation of the President or a State governor, but such a formal proclamation is not necessary.

Pretty much all i can think of so ,sorry.

union blockade

explanation:

the union blockade in the american civil war was a naval strategy by the united states to prevent the confederacy from trading.

the blockade was proclaimed by president abraham lincoln in april 1861, and required the monitoring of 3,500 miles (5,600 km) of atlantic and gulf coastline, including 12 major ports, notably new orleans and mobile. those blockade runners fast enough to evade the union navy could only carry a small fraction of the supplies needed. they were operated largely by british citizens, making use of neutral ports such as havana, nassau and bermuda. the union commissioned around 500 ships, which destroyed or captured about 1,500 blockade runners over the course of the war.

"the sepoy rebellion was the result of many, many influences and stressors on the cultures of india living under british rule. in britain, it's called the sepoy mutiny on the indian mutiny, but in india, it's called the first war of independence.

the main reason is concerned to the british paramountcy , the belief in british   dominance in india political, economic and cultural life had been introduced in india about 1820."

"they were forced to grow crops that benefited the colonizing nations instead of feeding their own people."