Republican Sen. James Lankford of Oklahoma said Tuesday that senators participating in President Donald Trump's impeachment trial have "got to be able to see" the book manuscript of former national security adviser John Bolton before they vote on whether to include witnesses in the proceedings.

Senate Minority Leader Chuck Schumer (D-NY) said the information coming out surrounding the articles of impeachment is reminiscent of the Watergate scandal.

Sen. Joni Ernst's recent comments about the impact of the impeachment inquiry on Democratic presidential candidate Joe Biden are reminiscent of Rep. Kevin McCarthy's comments on the impact of the Hillary Clinton Benghazi investigation.

Sen. Dick Durbin (D-IL) reacts to a proposal from Republicans to allow former national security adviser John Bolton to testify in President Trump's impeachment trial in exchange for testimony from Hunter Biden.

Revelations in the New York Times of a book manuscript by former national security adviser John Bolton claiming President Donald Trump told him he wanted to continue withholding aid from Ukraine until its government announced investigations "into Democrats including the Bidens" offer the latest twist in the impeachment saga. But the news is unlikely to change the political calculus of Republican senators who were already unlikely to convict the president.

CNN's John Avlon looks at President Trump's defense team strategy in his impeachment trial.

The virtually lockstep Republican defense of President Donald Trump so far during his impeachment trial marks a new milestone in the Senate's long-term evolution into a more partisan and regimented institution that demands unwavering party loyalty and punishes the freewheeling independence that characterized the great legislators through the body's history.

Democratic presidential candidate Joe Biden says Sen. Joni Ernst's (R-IA) comments about the impeachment testimony impacting Biden's chances in the state prove the real motivation behind Trump's attack on the former vice president and his son.

In reality, where we all live, the White House and Republicans scrambled Monday to deal with the situation created by John Bolton, who has blown the impeachment trial open with his leaked manuscript.

Donald Trump's impeachment trial defense is a perfect mirror for his presidency.