House Speaker Nancy Pelosi made an unprecedented and risky call when she held off on forwarding articles of impeachment against President Donald Trump to the Senate last month.

It sparked a political firestorm, and in the weeks since she has been criticized heavily.

But it looks like Pelosi’s gamble paid off.

Since she decided to delay the process, there have been at least 10 developments that have raised the stakes of the impeachment trial and forced the GOP into a corner.

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As soon as House Speaker Nancy Pelosi decided last month to withhold the transmission of articles of impeachment against President Donald Trump, critics asked whether it would be worth the risk.

The California Democrat made a historically unprecedented decision when she refused to transmit the articles to the Senate, the process which triggers an impeachment trial.

Pelosi’s move came after Senate Majority Leader Mitch McConnell and several other Republican senators indicated that they were not only working hand-in-glove with the White House ahead of the trial, but that they would not bring witnesses in to testify.

In response, Pelosi withheld the articles of impeachment, freezing the process while Democrats and Republicans duked it out over the terms of the trial.

Last week, Pelosi finally announced that she would transmit the articles, after McConnell modified his position by saying that the Senate would decide whether to call witnesses after it received the articles.

Republicans reacted by declaring victory, arguing that Pelosi had still essentially gained nothing.

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But a closer look at the timeline of events over the last several weeks paints a different picture. In fact, there have been at least 10 major developments since last month that dramatically raised the stakes of Trump’s impeachment trial and forced congressional Republicans into a tighter box.

The House voted to impeach Trump on December 18. A lot has happened since then:

On December 21 , the Center for Public Integrity obtained new documents showing that Mike Duffey, an official in the Office of Management and Budget (OMB), sent an email ordering a hold on military aid to Ukraine only 91 minutes after Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky. He requested that the recipients of his email keep the directive “closely held to those who need to know” because of “the sensitive nature of the request.”

, the Center for Public Integrity obtained new documents showing that Mike Duffey, an official in the Office of Management and Budget (OMB), sent an email ordering a hold on military aid to Ukraine only 91 minutes after Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky. He requested that the recipients of his email keep the directive “closely held to those who need to know” because of “the sensitive nature of the request.” On December 26 , cracks began forming in the Senate GOP ranks. Sen. Lisa Murkowski of Alaska said in an interview she was “disturbed” by McConnell’s declaration that he was working in “total coordination” with the White House ahead of Trump’s trial. “We have to take that step back from being hand-in-glove with the defense,” she said.

, cracks began forming in the Senate GOP ranks. Sen. Lisa Murkowski of Alaska said in an interview she was “disturbed” by McConnell’s declaration that he was working in “total coordination” with the White House ahead of Trump’s trial. On December 29 , The New York Times reported that Trump’s acting chief of staff and the head of OMB, Mick Mulvaney, was deeply involved in the administration’s efforts to freeze Ukraine’s military aid since as early as June 2019. Mulvaney’s actions sparked alarm from other officials, like his aide Robert Blair. In response to an email from Mulvaney asking whether it would be possible to hold back the aid, Blair replied said it would be possible but warned of consequences. “Expect Congress to become unhinged” if the White House tried to circumvent it by withholding aid, Blair wrote in an email, according to The Times. He also said it would fuel the narrative that Trump is pro-Russia.

, The New York Times reported that Trump’s acting chief of staff and the head of OMB, Mick Mulvaney, was deeply involved in the administration’s efforts to freeze Ukraine’s military aid since as early as June 2019. On January 2 , the national-security blog Just Security published even more emails showing how the Pentagon repeatedly warned that freezing Ukraine’s military aid could violate US law. Crucially, the documents showed that the Justice Department redacted several exchanges in which a Pentagon official raised concerns about the legality of the plan.

, the national-security blog Just Security published even more emails showing how the Pentagon repeatedly warned that freezing Ukraine’s military aid could violate US law. Crucially, the documents showed that the Justice Department redacted several exchanges in which a Pentagon official raised concerns about the legality of the plan. On January 6 , former national security adviser John Bolton said he would be willing to testify in Trump’s Senate trial. Bolton had previously refused to respond to a House subpoena for testimony because he wanted a court to rule on whether he should comply with the congressional subpoena or the White House’s order not to. Bolton’s announcement sent shockwaves through Washington. The former national security adviser is at the center of several key episodes in the impeachment inquiry, and his lawyer has hinted that Bolton has additional information. Bolton’s announcement also made him McConnell’s worst nightmare. A pivotal witness who was in the president’s inner circle had stepped forward and offered to testify in a trial about the president’s misconduct. Could McConnell and Senate Republicans really afford to ignore that?

, former national security adviser John Bolton said he would be willing to testify in Trump’s Senate trial. Bolton had previously refused to respond to a House subpoena for testimony because he wanted a court to rule on whether he should comply with the congressional subpoena or the White House’s order not to. On January 10 , Sen. Susan Collins of Maine told the Bangor Daily News that she and a “fairly small group” of Republican senators are working to make sure that witnesses are called during Trump’s impeachment trial. Collins’ revelation was significant; Republicans have a three-seat majority in the Senate, which means only four GOP lawmakers need to defect from McConnell to swing the balance.

, Sen. Susan Collins of Maine told the Bangor Daily News that she and a “fairly small group” of Republican senators are working to make sure that witnesses are called during Trump’s impeachment trial. Collins’ revelation was significant; Republicans have a three-seat majority in the Senate, which means only four GOP lawmakers need to defect from McConnell to swing the balance. On January 13 , it surfaced that hackers working for Russian military intelligence had hacked the Ukrainian natural-gas company Burisma Holdings in what appears to have been an effort to obtain dirt against former Vice President Joe Biden and his son, former Burisma board member Hunter Biden. Area 1, the California-based cybersecurity firm that discovered the hack, said Russia’s first attempt to breach Burisma was in November – around the same time that Trump was publicly calling for Ukraine to investigate the Bidens and Burisma.

, it surfaced that hackers working for Russian military intelligence had hacked the Ukrainian natural-gas company Burisma Holdings in what appears to have been an effort to obtain dirt against former Vice President Joe Biden and his son, former Burisma board member Hunter Biden. On January 14, McConnell conceded to reporters that he expects some Republicans to side with Democrats in calling for witnesses in Trump’s trial.

McConnell conceded to reporters that he expects some Republicans to side with Democrats in calling for witnesses in Trump’s trial. Also on January 14 , the House Intelligence Committee released a trove of previously unseen documents turned over by Lev Parnas, one of Trump’s and Rudy Giuliani’s Ukrainian associates involved in the ongoing controversy. The documents were explosive. They included handwritten notes from Parnas describing his responsibilities, which included getting Zelensky “to announce that the Biden case will be investigated.” They included text messages from Parnas, Giuliani, the GOP congressional candidate Robert F. Hyde, and the former Ukrainian prosecutor general Yuriy Lutsenko, in which they discussed tracking the movements of Marie Yovanovitch, then the US’s ambassador to Ukraine. The documents also included a previously unseen letter from Giuliani to Zelensky which destroyed the president’s last defense in the Ukraine controversy.

, the House Intelligence Committee released a trove of previously unseen documents turned over by Lev Parnas, one of Trump’s and Rudy Giuliani’s Ukrainian associates involved in the ongoing controversy.

The House of Representatives formally voted to transmit the articles of impeachment against Trump to the Senate on Wednesday, January 15.

But new evidence is still emerging.

In fact, Rep. Adam Schiff of California, one of the impeachment managers and the chairman of the House Intelligence Committee, told reporters that the panel is still reviewing thousands of documents Parnas turned over and that “it’s entirely possible there will be new and important evidence that comes out of the information that we’ve been receiving.”