[RonDog]

I am trying to find a link between the papers that ran the letters...

I think that one place to start is here is the automated "Letter to the Editor" generator here:

http://my.barackobama.com/page/speakout

After you pick a topic, and give them your ZIP code, they give you links to your local, regional and national newspapers.

From FReeper JimWayne:

...they even state that they will make sure that each newspaper believes that they are the only one getting the email...

...[and they] give you talking points next to the box in which you compose your letter.

[JimWayne]

Go to http://my.barackobama.com/page/speakout and check out the call to write letters about Sonia Sotomayor.

After entering a zip code, you can click on the link that says that the form does not work for you to save yourself from having to type your personal details. That will bring up the form in a single page format.

Check the talking points. Then check http://www.ironwoodinfo.com/community/opinion.htm and http://blogs.chron.com/txpotomac/2009/05/our_readers_speak_out_on_sotom.html
You have two identical letters there and they match with the version at barackobama.com.