ANALYSIS — Former President Donald Trump is on his way to a third consecutive GOP presidential nomination, but will Republicans who didn’t vote for him in the primary go for President Joe Biden? Probably not. 

Forty-nine percent of Republican caucus goers didn’t support Trump in Iowa. Forty-five percent of New Hampshire Republican primary voters didn’t vote for him either. And 40 percent of Republican primary voters in South Carolina supported former Gov. Nikki Haley. 

Considering Trump is the de facto incumbent in the GOP race, this could be a warning sign for the former president and two-time nominee that his support within the party is soft and there’s a risk that Republicans won’t support him in the general election.

But, in the end, history suggests the vast majority of Republicans will support him, even if they preferred an alternative in the primary or have concerns about his character and candidacy.

The bottom line is that party unity in the general election is powerful. In 2020, 94 percent of Republicans voted for Trump and 94 percent of Democrats supported Biden, according to the exit poll for CNN, ABC, NBC, and CBS. 

Party unity is also a trend in the midterm elections. In 2022, 96 percent of self-identifying Republicans voted for GOP candidates and 96 percent of Democratic voters supported Democratic candidates. It was a similar trend in 2018, when 95 percent of Democratic voters voted for Democrats and 94 percent of GOP voters supported Republican candidates. 

There was some slippage in party unity in the 2016 presidential election. Just 88 percent of Republicans supported Trump, but that didn’t prevent him from winning the race. He was probably helped by the fact that Hillary Clinton’s support among Democrats dipped as well, to 89 percent.

Given Trump’s more than 90 indictments in four different criminal cases or potential general fatigue with his style and approach, it’s possible that he slips below 90 percent among Republicans again this November. And it wouldn’t take a lot of party defectors in key states to potentially make a difference.

But there’s also no guarantee Biden maintains the typical 94 percent to 96 percent support among Democrats. In the most recent Gallup poll, conducted Feb. 1-20, 18 percent of Democrats disapproved of the job Biden was doing, and there’s concern the president’s support among some minority communities has softened. 

Of course those are national numbers in a race decided by a state-by-state Electoral College battle. But a look at the swing states shows the party unity trend is also strong at the state level and there’s been minimal or no difference in party unity in the last two presidential elections featuring Trump.

In 2020, Trump averaged 93 percent support from self-identified Republicans in the six states Biden carried narrowly (Arizona, Georgia, Michigan, Nevada, Pennsylvania and Wisconsin). Biden did slightly better and received 95 percent of Democratic voters in the same states. 

Swing state party unity in that election was greater than four years earlier, when Trump received an average of 90 percent of the vote from Republicans in 2016. Clinton received 90 percent of Democratic voters in the same states as well.  

It’s certainly possible that party unity dips below typical levels. But despite any concern about each of the likely nominees, the vast majority of partisan voters are likely to support their party’s nominee in the end.

Nathan L. Gonzales is an elections analyst with CQ Roll Call.