Why were the Crusades unsuccessful in establishing lasting political and religious control over the Holy Land?

Answer 1

Because you can't really change faith with a sword...true then as it is today. People will pretend to convert but they still practice their own brand of releigion in privacy ever after. Religion and violence...yum!

Answer 2

Politics, too far away from a renewable source of soldiers, internal fighting that sabotaged some of the Crusades, and by the end too many problems in Europe to go to the help of the kingdoms there when the Muslims attacked again.
Just for historic clarification to some answers above, those lands were Christian first, the Muslims invaded and settled down, the Crusades came a few centuries later to try to take them back and failed.

Answer 3

It`s quite a long story but basically the Crusaders were badly organized to begin with,they were not a unified group and many were led by Lords and nobility who could not always agree with one another.
They under-estimated the long journey and were constantly in need of food which caused great disatisfaction in their ranks.
They sometimes fell foul of local tribal leaders and chiefs and most of the foot soldiers were not even properly trained.

Answer 4

Because the Crusader States were relatively isolated from the rest of Christendom and were surrounded by the enemy. They were invaders holding onto stolen land who made little attempt to befriend their new neighbors.

Answer 5

Because the bible says man can not govern man successfully.
Every government that has ever been as fallen

Answer 6

because although complacent and taken somewhat by surprise, the muslims rallied and kicked out the invaders/occupiers.

Answer 7

Because a people cannot be subdued forever.

Answer 8

They got whipped by better fighters.