Anti-Trump Groups Determined to Soldier On After Indiana

— -- Even after Donald Trump’s projected win in the Indiana primary -- his 28th victory so far this primary season -- those determined to stop him say they will soldier on.

After Trump was deemed the winner of the Indiana competitor, Ted Cruz, his closest competitor in both delegates and votes, announced he was suspending his campaign. But Ohio Gov. John Kasich is still planning to compete until Trump reaches 1,237 bound delegates.

"Our strategy has been and continues to be one that involves winning the nomination at an open convention," Kasich's chief strategist, John Weaver, wrote in a memo after Trump's victory was announced. Weaver noted that the campaign had already secured a plurality of Indiana delegates that supported their candidate, should the convention advance to a second ballot.

“Obviously Trump’s victory in Indiana makes the road ahead more challenging,” Rory Cooper, a senior adviser for “Never Trump,” a super PAC devoted to stopping the front-runner, said in a statement just minutes after Trump's win was projected. “We will continue to seek opportunities to oppose his nomination and to draw a clear line between him and the values of the conservative cause.”

The statement did not detail what those upcoming plans would be, beyond saying their organization is “critical” to protecting candidates down the ballot in the fall. Cooper confirmed the statement still stands after the announcement that Cruz had suspended his campaign.

Katie Packer, chair of Our Principles PAC, which is dedicated to stopping Trump, wrote in a statement that there is still time to stop Trump from clinching the necessary 1,237 delegates needed for the nomination before the convention, and she and her group will therefore “continue to educate voters about Trump until he, or another candidate, wins the support of a majority of delegates to the Convention."

“There is more than a month before the California primary -- more time for Trump to continue to disqualify himself in the eyes of voters, as he did yet again today spreading absurd tabloid lies about Ted Cruz's father and the JFK assassination,” Packer wrote.

Almost 58 percent of the money spent in Indiana in the run-up to the election was in an effort to defeat Trump. Our Principles PAC spent $1.4 million on ads, according to an ABC News analysis of broadcast television ad data from CMAG/Kantar Media, but to no avail. The real estate mogul was handily projected to win the Hoosier State.

"Never ever ever Trump. Simple as that," Tim Miller, an adviser to Packer's PAC and the Jeb Bush campaign's former communications director, tweeted.

And earlier in the day, Republican strategist Mark Salter tweeted that if Trump were the nominee, he would support Clinton.

However, even as the anti-Trump forces persisted, GOP Chairman Reince Preibus seemed to be calling for party unity, maintaining in a tweet that Trump will be the presumptive nominee. According to GOP rules, a candidate is not the presumptive nominee until they have 1,237 bound delegates.

Trump currently has 1,049, according to ABC News data. Kasich has 153.