Presidents Biden and Trump swept their Pennsylvania primaries on Tuesday, but separate protest votes within each party signal growing discontent among some Republicans and Democrats toward their frontrunners — in a critical battleground state.

Ambassador Nikki Haley — despite dropping out of the race more than a month ago — took nearly 17 percent of the Republican vote in Pennsylvania’s primary on Tuesday, as Mr. Trump secured 83 percent of the more than 95 percent of votes counted so far. Opposition to Mr. Trump was especially on display in southeastern Pennsylvania in the Philadelphia area, with 25 percent of Republican voters at Chester and Montgomery counties casting their votes for Mrs. Haley. 

When Mrs. Haley suspended her campaign in March, she called on Mr. Trump to unify the Republican Party. “It is now up to Donald Trump to earn the votes of those in our party and beyond it who did not support him, and I hope he does that,” she said in a speech at Charleston, South Carolina. “At its best, politics is about bringing people into your cause, not turning them away. And our conservative cause badly needs more people. This is now his time for choosing.”

Yet, Mr. Trump appears to have made little effort to appeal to her supporters so far. As Mrs. Haley snagged some 157,000 Pennsylvania Republican voters, that chunk could be critical to Mr. Trump in the battleground state when it comes to the general election. 

Pennsylvania’s recent elections have come down to tight margins, as Mr. Biden won the state by only slightly more than 80,000 votes in 2020, while in 2016, Mr. Trump secured only 44,000 more votes than Senator Clinton — both lesser margins than the 157,000 votes for Mrs. Haley on Tuesday. 

Meanwhile, preliminary results indicate Mr. Biden took slightly more than 93 percent of Democratic primary votes in Pennsylvania, as he faced another uncommitted protest vote over his handling of the Israel-Hamas war.

“A large majority of registered Democrats are frustrated, disappointed, and horrified by the Biden administration’s unwavering support for Israel’s genocide in Gaza,” write-in organizers in Pennsylvania wrote, noting Mr. Biden’s tight winning margin in 2020.

The “uncommitted” write-in campaign said it had far exceeded its goal of 40,000 write-ins, with preliminary results indicating more than 57,000 write-ins for the Democratic president in the Pennsylvania primary so far.

Because Pennsylvania does not offer an “uncommitted” option on its ballot, it’s unclear so far who or what the voters wrote in, but it signals a possible protest vote against Mr. Biden. The “uncommitted” vote effort against Mr. Biden has seen support in a slew of other states, as the Sun has reported, including more than 100,000 voters in Michigan and significant support in states including North Carolina, Minnesota, Massachusetts, and Colorado.