Sen. Cory Gardner (R-CO) is a “no” on subpoenaing additional witnesses in the Senate impeachment trial, according to a report.

“I do not believe we need to hear from an 18th witness,” Gardner said in a statement to ColoradoPolitics.com. He continued:

I have approached every aspect of this grave constitutional duty with the respect and attention required by law, and have reached this decision after carefully weighing the House managers and defense arguments and closely reviewing the evidence from the House, which included well over 100 hours of testimony from 17 witnesses.

News of Gardner’s “no” vote comes after increasing confidence by Republicans that no additional witnesses will be called and the trial could wrap this week.

Democrats need four Republican senators to join them in calling for additional witnesses to testify.

On Tuesday evening, some reports indicated Republicans did not have enough votes to block that from happening at the moment, but that they could get there by Friday.

Gardner, who faces reelection this year, had been closely watched by Democrats as a possible vote for witnesses. His “no” decision is a potential sign that Republicans will maintain enough unity to block additional witnesses.

Senate Republicans appeared mostly unified against additional witnesses until a Sunday New York Times report alleged that a draft manuscript of former National Security Adviser John Bolton’s book said that President Trump wanted to hold security aid from Ukraine until they conducted political investigations.

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