How did the mountain ranges in northern and western regions india. remain independent for thousands of years

india was surrounded by mountain ranges. enemies could not get over the mountains easily at all. so they didn't even try. the mountains were excellent physical barriers.

i would say that the politicial parties from state to state varies.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.