For transcripts of news broadcasts and speeches produced in the last 30 years use:

• Nexis Uni provides access to many major news broadcasts and political transcripts. Choose Sources from the top menu and search for transcripts.
• Factiva also has a collection of transcripts. Select Search, then Search Builder from the top menu. Open up "All Sources,” use the pulldown menu to select "Sources by Type," and select Transcripts. Or, type rst=ttpt AND "your search terms" into the Free Text Search box.
• Newsbank is another news resources that includes transcripts. From the A-Z Source List, select Type from the drop-down and search for transcript.