Classify the following document as either an email, article, letter, or tweet.
WASHINGTON (CNN) -- A wide-open presidential race and a willingness by candidates, interest groups, unions and corporations to buy TV time will lead to historic spending for political and issue-advocacy advertising in the 2008 election cycle, an analysis shows.
This is an article.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:
Classify the following document as either an email, article, letter, or tweet.

### Input:
WASHINGTON (CNN) -- A wide-open presidential race and a willingness by candidates, interest groups, unions and corporations to buy TV time will lead to historic spending for political and issue-advocacy advertising in the 2008 election cycle, an analysis shows.

### Response:
This is an article.