Trump isn't the first former president to be subpoenaed by Congress

Former President Donald Trump will have to decide how to handle the subpoena that the House Jan. 6 committee voted to issue to him Thursday, though as vice chair of the committee Rep. Liz Cheney pointed out, he's not the first president or former president to receive a congressional subpoena. The committee is demanding documents and testimony under oath from Trump, because it has concluded it was Trump who was at the center of the assault on the Capitol and the efforts to overturn the 2020 presidential election. 

On April 11, 1974, Richard Nixon became the first-ever sitting president to be subpoenaed by a congressional committee, as the House Judiciary Committee sought material related to an impeachment inquiry against him. Nixon turned over transcripts and conversations, but the committee believed he wasn't being completely forthright. 

By 1974, Congress had already subpoenaed former presidents.