I agree with you measured approach. As you have mentioned Powell, I have to say that I have always thought his infamous speech more reflected the concerns he was receiveing from his constituents on imigration...than anything else.
I read it again tonight...
http://www.telegraph.co.uk/opinion/main.jhtml?xml=/opinion/2007/11/06/do0607.xml
...so much of what we read and discuss these days, is deliberately taken out of context...but that's politics!