If I successfully perform an Intrigue Contest in a neutral province containing an army in mid campaign what happens to the army? Does the campaign end and they now have to start over with a siege?

Page 17 of the rules: "A player can never attempt an intrigue contest in a savage province, a home province, or a province that contains an enemy fort, city , or enemy army . (Bold mine.) So it can't happen...

Hi, I understand this rule, but once i was trying to perform an intrigue, I have failed, but in the next round another player moved his army to the neutral province (containing), and he contested that province in one round using forced march. The question is: What should I do with my emissary, which is still standind on that province? Thx.

Emissaries have no trouble standing in provinces with enemy armies. They just can't perform an intrigue contest when an army is standing there.

In short: leave your emissary there. He enjoys diplomatic immunity from the enemy swords.

Also, your emissary can generate gold with an Intrigue action you have. I forgot the name, just check your cheat sheet.