The memorandum calls for paying employees at the Coast Guard, Federal Emergency Management Agency and Cybersecurity and Infrastructure Security Agency who have gone without pay during a record-long shutdown.
In his address, President Trump did not define a clear path out of the war but said the United States would hit Iran “extremely hard” in the next few weeks.
The investigation comes as administration officials have fielded complaints about how Kristi Noem’s top adviser, Corey Lewandowski, dealt with companies seeking federal contracts.
Chief Justice John G. Roberts Jr. and Justices Elena Kagan, Brett M. Kavanaugh and Amy Coney Barrett attended President Trump’s State of the Union address in February.