How strong is Trump’s Senate firewall?

September 29th, 2019

A guest slot from Fishing

Almost three years ago, a few days after Trump was elected, I wrote a thread on this site saying that

  • the Democrats would be able to find an excuse to impeach Trump if they gained control of the House in 2018
  • for that reason, 2019 would be the peak year of danger for Trump in this respect
  • but I expected that the Senate would acquit, because of its likely Republican majority following the Midterms.

Given the events of the past week, and in particular the news that the Judiciary Committee will consider recommending Articles of Impeachment to the House, I thought it might be worth looking at the last point in more detail.  In particular, what would it need for that Senate firewall to crack? Is the predictit.org implied probability of 16% too high or too low?

Reaction to the Ukranian phone call has been split largely, but not entirely, along party lines.  There was no direct, overt, quid pro quo between Trump and his interlocutor, but on the other hand a reasonable person could infer an implicit deal could have been agreed.  No evidence has yet come to light that Trump obstructed justice, but the classification of the record of the phone call seems fishy. So there is some smoke, but no fire. The remainder of this thread assumes that this will continue to be the case.

The precedent: The Senate must vote to convict (and then remove from office – the only possible penalty under the Constitution) a President by a two-thirds majority after a trial in which the Chief Justice of the Supreme Court presides.  Three Presidents have faced impeachment:  Andrew Johnson (who was a Democrat, though he had been Lincoln’s Vice-President),  Richard Nixon,  and Bill Clinton

Each faced a Senate controlled by the opposing parties, though in the last two cases, votes from the President’s party were required.  Johnson and Bill Clinton managed to avoid removal from office, though there is little doubt that Nixon would have been removed, had he not resigned.

Composition of the Senate  Trump faces a friendly, though not entirely safe, Senate.  Republicans hold 53 seats. To get to the two-thirds supermajority needed to replace Trump with Vice-President Pence – 67 Senators – 20 Republicans must join the 47 Democrats if the latter are united.  The conventional wisdom is that there is little realistic prospect that he will be removed from office unless the investigation finds something truly extraordinary.  

How can we judge if this is right?  How likely is it that a significant number of the Republican Senators seeking reelection in 2020 will cross party lines and vote to convict Trump, without an absolutely ironclad case of a very serious crime?  In the United States, Senators are much less subject party discipline than MPs are over here. Conjecturing how they will vote is much more art than science. I should say there are three factors we can look at: whether the Senator is a “Never Trump”-er or an “Always Trump” -er or something in between; whether the Senator is up for reelection this year in which case public opinion may influence them more; and whether the Senator has commented on the allegations yet or not.

The class of 2014  If public opinion starts to tip, the strange, staggered electoral system whereby one-third of Senators face reelection every two years could start to favour impeaching Trump.  In 2018, Democrats held 25 of the seats up for reelection (including two Independents who caucused with them) and Republicans held eight. This meant that there was no realistic prospect of the Republicans losing their majority.  However, in 2020, it is the Republicans’ turn: 23 of their Senate seats are to be contested, compared to 12 Democrats. It is notable that, of the five Republicans who crossed party lines to vote to acquit Clinton of perjury in 1999, three (Chafee, Jeffords and Snowe) were facing reelection in 2000 (and one of the two others, Arlen Specter, subsequently defected to the Democrats).  They were more vulnerable to pressure from the public, who were mostly against removing the President from office. If all 23 of the Republican incumbents start to feel pressure from their voters or donors, Trump’s firewall will look a lot less secure.  

However, of the 23 up for reelection:


  • 15 are safe Republican seats, so incumbents are much less likely to feel pressure to impeach from 2020 voters.  Only Graham (South Carolina), Sasse (Nebraska), Daines (Montana) and maybe Cotton (Arkansas) have much of a record of voting against Trump, but all would have to worry about retaining the loyalty of their base and party in this and future elections if they voted the wrong way.  
  • of the remaining eight, two (Isaakson (Georgia) and Roberts (Kansas)) are retiring, so do not need to fear the voters at all.  Roberts is very pro-Trump, Isaakson slightly less so, but still mainstream Republican. Perdue (Georgia) and Ernst (Iowa), are Trump loyalists. McSally (Arizona) and Tillis (North Carolina) are broadly loyal to Trump and have perhaps become more so since facing conserative primary challengers.  Only Gardner (Colorado) and Collins (Maine) seem to me likely to back a serious impeachment challenge – indeed Collins has voted more against Trump’s positions than in their favour in this Congress!


So I think Democrats would be doing amazingly well if five Republican Senators from the 2014 class voted to convict Trump – indeed I would be surprised if more than a couple did so.

The classes of 2016 and 2018 What about the other Republicans in the Senate?  23 of the 30 can be considered Trump loyalists, at least if we judge by the votes they have cast.  It would need an earthquake for them to vote to convict him. Of the seven more independent GOP Senators, three – Murkowski (Alaska), Daines (Montana), Romney (Utah) – have expressed serious concern about the Ukranian phone call, while three (Paul (Kentucky), Hawley (Missouri) and Lee (Utah) have defended Trump.  One (Moran (Kansas)) has yet to comment.

At most three or four of the Republican Senators may switch sides.

Conclusion A Judiciary Committee investigation is an unpredictable tool, but Trump’s firewall should hold.  From what we know at the moment, I cannot see Democrats getting the 20 Republicans they need to convict and remove Trump from office.  Pressure from voters may cause those facing reelection this year to waver more than other Senators, but I doubt it will be enough. The current predictit.org odds of 16% therefore look, if anything, too high.  President Pence will have to wait.