Updated at 1:58 p.m. ET

The first full day of the Trump impeachment trial will be dominated by partisan fighting over the rules of the proceedings.

Senate Majority Leader Mitch McConnell released his resolution outlining the next steps, including a week of hours-long opening arguments, on Monday.

Watch the floor action live.

Updated at 9:09 p.m. ET

On the eve of arguments in President Trump's historic impeachment trial, Senate Majority Leader Mitch McConnell has revealed his long-awaited resolution setting the initial parameters for how the process will play out.

Democrats are already slamming the four-page resolution, which they say will place time limits on arguments and departs heavily from President Clinton's impeachment trial of 1999. The McConnell resolution does have some similarities to the Clinton-era resolution, however.

Weeks before the first votes of the 2020 presidential election, Americans report a high level of concern about how secure that election will be and worry about the perils of disinformation, according to a new NPR/PBS NewsHour/Marist Poll.

Forty-one percent of those surveyed said they believed the U.S. is not very prepared or not prepared at all to keep November's election safe and secure.

Updated at 12:58 p.m. ET

The White House is offering a fiery legal response to the articles of impeachment, in an executive summary of a legal brief obtained by NPR.

Decrying a "rigged process" that is "brazenly political," President Trump's legal team accuses House Democrats of "focus-group testing various charges for weeks" and says that "all that House Democrats have succeeded in proving is that the President did absolutely nothing wrong."