On Friday, President Donald Trump continued trying to undermine an intel whistleblower's complaint alleging that he threatened to withhold military aid from Ukraine unless authorities in the country gave him dirt on Joe Biden.

"Sounding more and more like the so-called Whistleblower isn’t a Whistleblower at all," he wrote on Twitter. "In addition, all second hand information that proved to be so inaccurate that there may not have even been somebody else, a leaker or spy, feeding it to him or her? A partisan operative?"

Writing in the Washington Post, columnist Philip Bump notes that Trump's strategy appears to be to undercut the complaint by claiming it's partisan and second-hand. Bump re-asserts the validity of the complaint.

"The answer is simple. While much of what the complaint includes is indeed secondhand or based on news reporting, those are hardly disqualifying," he writes.

"The news reports are mostly citations of Trump’s mentions of the situation with Ukraine or references to Trump-friendly articles at the Hill. And those secondhand assertions in the complaint (read them here) that can currently be verified have been verified — by White House comments or in the rough transcript (read it here) of the July 25 call between Trump and Ukrainian President Volodymyr Zelensky."

"It’s sounding more and more as if the so-called whistleblower is just as credible as the intelligence community’s inspector general and a subsequent review by the Office of Legal Counsel determined him or her to be," he concludes.