Donald Trump
Conservative paper gets tough with TrumpIsaac Brekken/Getty

The conservative Wall Street Journal has told GOP presidential candidate Donald Trump in an editorial to straighten out his stumbling campaign by the end of summer or turn the race over to his running mate.

"He needs to stop blaming everyone else and decide if he wants to behave like someone who wants to be president – or turn the nomination over to Mike Pence," said the newspaper.

"Mr Trump has alienated his party and he isn't running a competent campaign," the editorial noted. "If they can't get Mr Trump to change his act by Labor Day, the GOP will have no choice but to write off the nominee as hopeless and focus on salvaging the Senate and House."

That message echoed a recent call by 70 Republicans in a letter to the GOP that party funds be withheld from the failing Trump campaign to invest instead in other races.

The editorial also lashed Trump for blaming the media for all of his problems.

"Trump has made it so easy for the media and his opponents," said the editorial. "Trump prefers to watch the cable shows rather than read a briefing paper. He thinks the same shoot-from-the-lip style that won over a plurality of GOP primary voters can persuade other Republicans and independents who worry if he has the temperament to be commander in chief."

The WSJ also questioned whether it is "so hard" to read briefing papers on important national topics. "Apparently so," it concluded.

Polls show that Trump is "on the path to losing a winnable race," the newspaper said. The GOP nominee "thinks the crowds at his campaign rallies are a substitute for the lack of field organisation and digital turnout strategy. And he thinks that Twitter and social media can make up for being outspent $100 million-to-zero in battleground states."

With 80 days left before the election, Trump's "window for a turnaround is closing," the paper warned.

The Trump campaign refused to comment on the editorial. Trump did not respond directly, but did say in a Tweet that he has remained "true to [him]self."

The paper and the candidate have clashed in the past. Late in 2015, the WSJ said it was "exhilarating" to be attacked by Trump after the nominee called its staff "dummies."

The insult came after an editorial said it was not "obvious" after a Republican debate that Trump had "any idea what's in the Trans-Pacific Partnership" that he opposes.