From Roll Call: Sen. John McCain (R-Ariz.) has unveiled a proposal to limit donations to 527 organizations to $25,000 per person each year, or $50,000 each election cycle, that if enacted could be a huge blow to the groups’ hopes of being a force in the 2006 elections. Those groups raised and spent more than $500 million in the previous cycle, with many of the organizations relying on multimillion-dollar donations from wealthy individuals to fund their activities.