In the half hour since we posted on Service Employee International Union’s 2008 political activity and lobbying expenditure numbers, the U.S. Postal Service delivered the copy of the U.S. Chamber of Commerce’s form 990 that we requested yesterday.

On page 3 of part B of the return, the Chamber reports having spent a little more than $63 million on lobbying and political expenditures. They appear to file on a calendar year basis, so that number would be for 2008. That’s less than the $67 million the SEIU disclosed spending (see the post immediately below) but note that at this point we have no confidence in comparing these numbers whatsoever, as we have yet to ascertain whether “lobbying and political activities” are defined the same way for labor unions as they are for trade associations.

One other thing of interest: the Chamber discloses spending more than $21 million on 527 activities.*

None of the information is itemized–there’s nothing like the hundreds of expenditures for political activities that labor unions had to file on the LM-2s.

*–corrected. Thanks to Bradley Peck of the Chamber for pointing out the distinction that this is not $21 million worth of contributions to other 527 organizations. Sloppy wording on my part in the original version of the post.