Today could be the last day of the exhausting Senate impeachment trial, depending on whether a handful of moderate Republican senators vote to hear additional witnesses.  If the Senate decides that it has heard enough, they will then vote on removal of Donald Trump as president of the United States, which will undoubtedly fall far short of the 67 votes needed to evict him from the White House.  While it seems that nearly all Republicans are uninterested in hearing additional testimony, many haven't considered the tremendous upside that witnesses could bring to the GOP. 

Republicans believe they are winning the case, as there isn't clear evidence that President Trump linked aid to Ukraine with calling investigations on Joe Biden.  Plus, even if there was such a linkage, Republicans such as Senator Ted Cruz (R-Texas) say that wouldn't be illegal or impeachable.  In a courtroom, the prevailing theory would be to end the trial and celebrate acquittal.  If you're winning, there's no need to take any risks.  But this is an impeachment trial, and there are political implications.  Senate Republicans are seemingly not considering the political benefits of calling witnesses; their only goal seems to be acquittal, as if this were a standard criminal trial. 

The past few days have made it abundantly clear: the first witness for Democrats would be President Trump's former national security adviser, John Bolton, and the Republicans' highest priority witness would be Hunter Biden, son of former vice president Joe Biden.  If these witnesses are called, the next phase will allow Republicans to run away with the lead. 

The Republicans, being the Senate majority, would likely call their witness first.  The advantage here for Republicans is that they can highlight and expose the corruption in Ukraine that President Trump was targeting in the infamous July 25 call.  This would bolster President Trump's claims that there are sufficient grounds for investigation into the Bidens, thereby alienating the accusation that investigations were started in bad faith.  Hunter Biden's former employer, Burisma Holdings, and Burisma's owner, Mykola Zlotchevsky, have been accused of money-laundering by the government of Latvia.  Burisma has been investigated continuously for years for all kinds of white-collar crimes.  Every political party wants to have voters believe that it will clean up corruption, and here is the GOP's chance to make a point of it.  Candidate Trump ran with the slogan of "drain the swamp" and now has a chance to cash in on that promise.  If Hunter Biden pleads the Fifth, Joe Biden can kiss his candidacy goodbye. 

There are questions being raised about how the Bidens obtained their wealth and the legality of potential conflicts of interest.  When asked by ABC News reporter Amy Robach: "If your last name wasn't Biden, do you think you would have been asked to be on the board of Burisma?," Hunter Biden responded by saying, "I don't know, probably not..."  However, former vice president Biden said he never discussed overseas business with his son.  When asked about these sketchy deals on the campaign trail, Joe Biden has grown increasingly defensive.  Pressing this issue will certainly score political points for Republicans.  

As for the Democrat witness John Bolton, it isn't particularly clear if he would be able to testify without preceding litigation by Trump's legal team.  The president has used executive authority to withhold some of his other advisers from testifying, and litigation might draw out long enough to tire out voters who have, believe it or not, spent dozens of hours watching C-SPAN. 

Given the assumption that Bolton does testify, the worst-case scenario for President Trump is that Bolton expands on the allegations in the leaked manuscript from his most recent book and testifies that there was a linkage between the foreign aid and corruption investigations.  While this allegation hurts politically, Trump's legal team can point to many reasons to negate it.  For one, the timing of Bolton's upcoming book The Room Where It Happened, which will be published March 17, raises eyebrows, as he is in full marketing mode.  Secondly, there are already multiple witnesses called by Democrats who said there was no linkage, including Ambassador Kurt Volker, Ambassador William Taylor, and deputy assistant Tim Morrison.  In addition, Ukrainian president Volodymyr Zelensky said with regard to the July 25 call that "we had good phone call.  It was normal, we spoke about many things.  I think, and you read it, that nobody pushed me."  The only witness to claim a quid pro quo was Ambassador Gordon Sondland, who later walked it back as only his "presumption."  Republicans have these justifications to fall back on in case John Bolton tries to confirm the alleged quid pro quo.  Lastly, President Trump can also argue that Bolton's explanation is exaggerated due to Bolton's reportedly hostile exit from the White House in September.

Consider the downside for Republicans if additional witnesses aren't called.  If Bolton doesn't speak in front of the Senate, the Democrats would accuse Republicans of a cover-up throughout the election season.  Bloomberg ads would ask what Republicans are hiding, and accuse Republicans of blocking witnesses without any regard for bipartisanship.  Democratic candidates Bernie Sanders and Elizabeth Warren would ask why their Republican Senate colleagues don't want to hear the whole truth.  The eventual Democrat nominee will bring a copy of Bolton's new book with them everywhere, quoting it in stump speeches and mentioning it at campaign rallies.  Republicans can prevent these talking points by letting Bolton air his grievances now, 10 months before the election. 

With witnesses, Republicans can continue their winning streak by exposing the Bidens.  The GOO can avoid the Democrat talking point that loose ends remain. Republicans have a winning argument, so they should prolong the platform on which they can argue it.  The GOP has an opportunity to run up the score, and they would be wise to do exactly that.

Image credit: Nick Youngson, Alpha Stock Images, CC BY-SA 3.0.