For more, here: https://www.foxnews.com/politics/trump-sends-letter-tod-pelosi-pledging-to-go-ahead-with-state-of-the-union-address
Interesting letter.
Dear Madam Speaker:
Thank you for your letter of January 3, 2019, sent to me after the long Shutdown began, inviting me to address the Nation on January 29th as to the State of the Union. As you know, I had already accepted your kind invitation, however, I then received another letter from you dated January 16th, 2019, wherein you expressed concerns regarding security during the State of the Union Address due to the Shutdown. Even prior to asking, I was contacted by the Department of Homeland Security and the United States Secret Service to explain that there would be absolutely no problem regarding security with respect to the event. They have since confirmed this publicly.
Accordingly, there are no security concerns regarding the State of the Union Address. Therefore, I will be honoring your invitation, and fulfilling my Constitutional duty, to deliver important information to the people and Congress of the United States of America regarding the State of our Union.
I look forward to seeing you on the evening on January 29th in the Chamber of the House of Representatives. It would be so very sad for our Country if the State of the Union were not delivered on time, on schedule, and very importantly, on location!
Sincerely,
Donald J. Trump