Note that the Newsweek censure question mentions "warrantless wiretapping" but doesn't specify that American citizens were wiretapped. The ARG poll said this:

Do you favor or oppose the United States Senate passing a resolution censuring President George W. Bush for authorizing wiretaps of Americans within the United States without obtaining court orders?
3/15/06     Favor     Oppose     Undecided
All Adults     46%     44%     10%
Voters     48%     43%       9%
Republicans (33%)     29%     57%     14%
Democrats (37%)     70%     26%       4%
Independents (30%)     42%     47%     11%
Based on 1,100 completed telephone interviews among a random sample of adults nationwide March 13-15, 2006. The theoretical margin of error is plus or minus 3 percentage points, 95% of the time.

People need to pound on this until someone gets around to doing a new poll with questions specifying that citizens have been wiretapped without a warrant or court supervision of any kind.  A lot of respondents don't know that small detail. Being so informed makes respondents more likely to support censure, I'm sure.