House Speaker Nancy Pelosi has uninvited President Donald Trump from delivering the State of the Union address because of the partial government shutdown, saying that because of security concerns, it would be better to wait until the government has reopened, or for Trump to submit it in writing.

In a letter to Trump on Wednesday, Pelosi delivered the news that she wants to postpone the address from its preplanned January 29 date and work with the president to “determine another suitable date,” or for the president to deliver it in writing. Trump and Congress have been at an impasse for weeks over his refusal to sign a government funding bill unless it includes $5.7 billion for the construction of some 200 miles of wall at the US-Mexico border, and Pelosi said she’s looking to reschedule Trump’s speech once that issue is settled and the government is back up and running.

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The State of the Union address, since the start of modern budgeting in 1977, has never been delivered during a shutdown, Pelosi said. And during the 19th century and through Woodrow Wilson’s presidency, it was actually delivered in writing.

Pelosi focused most of her attention on security. She pointed out that in September 2018, Homeland Security Secretary Kirstjen Nielsen designated State of the Union addresses as “national special security events” (NSSEs) that need “the full resources of the Federal Government to be brought to bear” for the sake of safety and security.

“The extraordinary demands presented by NSSEs require weeks of detailed planning with dozens of agencies working together to prepare for the safety of all participants,” Pelosi wrote.

She also noted that the Secret Service, the lead federal agency responsible for coordinating and implementing security for NSSEs, and the Department of Homeland Security haven’t been funded for 26 days. Nine federal departments have been affected by the shutdown, including Homeland Security, Justice, and State.

Here's the letter from Pelosi uninviting President Trump to give the State of The Union address on January 29th pic.twitter.com/InuBKUV4FF — Justin Gray (@grayjustin) January 16, 2019

Nielsen said in a tweet on Tuesday afternoon that DHS and the Secret Service are “fully prepared to support and secure” the State of the Union.

The Department of Homeland Security and the US Secret Service are fully prepared to support and secure the State of the Union. We thank the Service for their mission focus and dedication and for all they do each day to secure our homeland. — Sec. Kirstjen Nielsen (@SecNielsen) January 16, 2019

It is still unclear whether the State of the Union will take place.

Pelosi’s latest move in an ongoing battle with the White House over the shutdown and funding the government. Pelosi has said she will not budge on providing money for Trump’s border wall.

CNN reporter Kaitlan Collins reported on Wednesday that Trump aide Stephen Miller and other speechwriters have for weeks been working on Trump’s State of the Union address — and were looking to focus on the government shutdown. It now looks like they won’t have that opportunity.

Update: Story updated with Nielsen’s tweet.