Dumbledore: Patronus and Dementors

[Caius Marcius]

No: HPFGUIDX 173634

One of the most delicious images in DH for me was during the Muggle-
Born trial sequence, where Umbridge's Cat Patronus rubs up against the 
inquisitors, keeping them safe from the dementors' baleful influence. I 
had always wondered how the likes of Cornelius Fudge was able to deal 
with dementors ("I've never seen them so angry," he says in PoA) 
without ill effect.

I believe that on her website, JKR said that the Patronus spell was 
invented by Dumbledore. We know from PoA how much Dumbldore detests 
dementors, and what a mistake it was for the Ministry to work with 
them. But did Dumbledore inadvertently make that unhealthy alliance 
possible through his creation of the Patronus spell, or is there 
another way to deal with dementors without the side effects?
 
    - CMC