Dems set to prosecute case at Trump impeachment trial amid speculation over which Republicans might convict

The House impeachment managers will begin their opening arguments on the merits of the impeachment of former President Donald Trump when the chamber convenes at noon on Wednesday, following a 56-44 Senate vote to move ahead with the trial Tuesday.

Meanwhile, speculation is running rampant about which Republicans may vote to convict Trump. The attention has mainly been on a group of moderate senators, but also includes Senate Minority Leader Mitch McConnell, R-Ky. Bloomberg reported Tuesday that McConnell hasn't decided how he'll vote on the final conviction question and has told other Republicans that their vote is a personal decision.

It's almost certain that 17 Republicans won't vote to convict Trump -- the number necessary for Democrats to reach the 67-vote supermajority threshold -- but the House impeachment managers are hopeful they can get more Republicans on board to deliver a stronger rebuke to the former president.

They made some progress in that direction Tuesday when Sen. Bill Cassidy, R-La., switched his vote from against the trial's constitutionality in a test vote forced by Sen. Rand Paul, R-Ky., last month to in favor of constitutionality. Cassidy had said his previous vote "was a vote in a moment in time" and that his Tuesday vote was because "the House managers had much stronger constitutional arguments. The president’s team did not."

"We were told that it would be completely partisan and locked from the last vote and it wasn’t, so people's minds are open," lead House impeachment manager Rep. Jamie Raskin, D-Md., said. "We haven't started the evidence yet, but we're starting tomorrow."