Biden must win back 2020 voters. Trump only cares about MAGA. Let the election begin.

Primary elections are family squabbles, the old political saying goes, that the family puts behind them and unites to fight everyone else in the general election.

This makes 2024 the year of dysfunctional families.

Consider how President Joe Biden and former President Donald Trump responded Wednesday, when Nikki Haley finally stepped out of the Republican primary.

Trump posted on his social media website that the former South Carolina governor "got TROUNCED" in the Super Tuesday primaries while claiming that many of her votes came from "Radical Left Democrats." He followed that up with an incongruous and unconvincing invitation to those same Haley supporters to back him.

"I hope she stays in the 'race' and fights it out until the end," added Trump, after his campaign had repeatedly called for Haley to drop out and endorse him.

Were you expecting magnanimity from the would-be MAGA king?

The Trump political family turned on Haley

Haley did half of what Trump wanted by dropping out, stopping well short of an endorsement. Which, of course, enraged him.

Trump lives in a bubble where fealty flows in only one direction – toward him. And Haley's short speech about dropping her bid missed that mark two ways.

First, Haley said she will "not stop using my voice for the things I believe in" while taking barely veiled shots at Trump's brand of isolationism when it comes to Russia's aggression in Ukraine and China's threats to Taiwan.

And then, while congratulating Trump on what clearly will be his nomination for the presidency, she dared to suggest that he still has some work to do.

"It is now up to Donald Trump to earn the votes of those in our party and beyond it who did not support him," Haley said. "At its best, politics is about bringing people into your cause, not turning them away."

This is not what Trump was looking for. He expects vanquished adversaries to grovel for his approval, to endorse without condition or expectation.

Biden's political party praised Haley for her 'courage'

Compare that with how Biden greeted Haley's exit

The president who defeated Trump in 2020 on Wednesday touted Haley's criticism of Trump, which grew stronger and more vibrant as other would-be contenders fell out the field.

"It takes a lot of courage to run for president – that's especially true in today's Republican Party, where so few dare to speak the truth about Donald Trump," Biden said in a statement after she dropped out. "Donald Trump made it clear he doesn't want Nikki Haley's supporters. I want to be clear: There is a place for them in my campaign."

Haley is a lens through which we see the cravings of the president and his predecessor.

Trump wants obedience. He and the Republican National Committee that he is consuming have been stepping up threatening rhetoric about there being no space in the party for anyone who does not embrace Trump.

Here's what his daughter-in-law Lara Trump had to say on the conservative broadcaster Real America's Voice Monday while talking about her bid to take over at the RNC: “Anyone who is not on board with seeing Donald Trump as the 47th president and America-loving patriots all the way down the ticket being supported by the RNC is welcome to leave."

Third-party candidate? No Labels tells me they don't want to be a 2024 election spoiler. It's time to prove it.

Biden wants votes. Democratic votes. Independent votes. Republican votes. Any votes. He knows the presidency is won through coalition-building, not by bullying voters with derision and division.

Biden isn't turning anyone away. And his team is clearly reading Haley's playbook now for tips.

Biden knows enough to go after Haley voters

In a five-page memo released early Wednesday, Biden's campaign managers crunched the numbers and cited Haley's "significant shares of votes" that she won in Iowa, New Hampshire, South Carolina and Michigan.

These were states nobody expected Haley to win. But she cut into Trump's margins with Republican voters who don't find his "Make America Great Again" act so endearing.

"Trump can't expand his reach beyond the MAGA base – in exit poll after exit poll, he has consolidated support only among the most conservative voters," campaign managers Jen O'Malley Dillon and Julie Chavez Rodriguez wrote.

The memo also highlighted Trump's troubles among moderates in suburbs, a group of voters who swung away from MAGA world in elections since 2020.

"A significant share of moderate and Haley voters across the country are saying that Trump cannot count on their votes in a general election," the memo said.

Biden is still battling the 'uncommitted' voters

Biden, of course, has problems in his own house.

The economy is on the upswing, but voters still don't seem to feel or believe that. Biden is 81 now and showing it, which seems to draw more attention than clearly age-related blunder from the 77-year-old Trump.

And Israel's expansive military incursion into Gaza after the horrific Oct. 7 Hamas attacks is driving a wedge between Biden and young, progressive voters he needs in his November coalition.

That manifested as a protest vote in Michigan last week, when 13% of the ballots in the Democratic primary went to "uncommitted."

Haley can still save us: Nikki Haley and her voters still have a chance to be heroes. They need to vote for Biden.

As I noted Super Tuesday, six of the 15 states voting in Democratic primaries that day had ballots that offered options of "uncommitted/noncommited" or "no preference."

Nearly 19% of Minnesota Democratic primary voters cast ballots for "uncommitted" Tuesday, while nearly 13% voted "no preference" in North Carolina and 9% of the votes were for "no preference" in Massachusetts.

Now it comes down to which political family can remain united

Biden needs to win back to his family 2020 supporters who now are turning away and considering a vote for a third-party candidate or just not casting a ballot this year. He knows that. He's working on it.

But Trump has spent the better part of 2024 telling members of his family that he's ready to throw them out of the house.

In late January, he said anyone contributing to Haley's campaign would be “permanently barred from the MAGA camp.” In Virginia this month, Trump claimed his MAGA base makes up "96%, maybe 100%" of the Republican Party while pledging to expel people now seen as moderates, like U.S. Sen. Mitt Romney of Utah.

The old style of politics saw Democrats move to the left end of the political spectrum to win competitive presidential primaries while Republicans pivoted to the right. The primary winners on both sides then spend the summer and fall trying to move to the middle, to appeal to the largest possible group of voters.

These primary results have been a foregone conclusion for months now. We all knew we were getting a Biden-Trump rematch. But only Biden is driving a general election campaign these days. Trump is spinning his wheels in MAGA mud. And that may not get him where he wants to go in November.

Follow USA TODAY elections columnist Chris Brennan on X, formerly known as Twitter: @ByChrisBrennan

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This article originally appeared on USA TODAY: Trump is all MAGA. Biden has to fix his base. Welcome to the election