Officials say that threatening letters -- one of which contained white powder -- were sent to Sen. John McCain's campaign offices in Colorado and New Hampshire.
More RNC Coverage | Veepstakes Interactive
The Democratic National Convention is right around the corner, with the Republican National Convention on its heels. Get the inside scoop on both conventions in our special sections. More DNC Section | RNC Section
This Day In Political History
We've created a gallery, updated daily, of important moments in U.S. political history in November. More
The Democrats Meet In Convention In A Little Over Two Weeks. CNN Deputy Political Director Paul Steinhauser And CNN's John Lisk Talk About A Little Disagreement Over Hillary Clinton At The Convention. Listen
John McCain's Ad Comparing Barack Obama's Campaign To Paris Hilton Draws A Response From The Hotel Heiress. CNN Political Contributor Roland Martin And CNN's John Lisk Take A Look Listen
CNN Deputy Political Director Paul Steinhauser And Bill Caiaccio Discuss Why Vice President Dick Cheney Might Not Be At The Republican Convention. Listen
Some scheduled speakers at the Republican National Convention could be on John McCain's short list of running mate picks. So why are some conservatives nervous? More
