One month after announcing his support for Donald Trump, Marco Rubio still believes that the presumptive GOP nominee is unfit to be commander-in-chief. "I stand by everything I said during the campaign," the Florida senator told THE WEEKLY STANDARD on Thursday when asked if he still believes Trump cannot be trusted with access to the country's nuclear weapons codes.

During the campaign, Rubio said that Trump was "dangerous" and that we must not hand " the nuclear codes of the United States to an erratic individual."

Rubio's comment Thursday afternoon came as Trump's character and temperament faced a new round of scrutiny following Trump's racial attack on a federal judge. Rubio condemned Trump's remarks but did not withdraw his support from the GOP nominee.

Asked if his support for Trump is now unconditional or if it's possible Trump could do something to lose Rubio's vote, Rubio declined to discuss the matter. "I don't have anything new to add from what I've already said. I've talked about it all week long," he said.

Rubio also declined to discuss the specific reasons why Hillary Clinton is such a threat that he decided to back Trump despite believing the Republican nominee is temperamentally unfit to have access to America's nuclear weapons arsenal. "I just don't have anything new to add to the campaign. When I'm here in the Capitol I'm trying to focus on my work," Rubio said. "Now I'm focused on [things] like Zika. Write a story on Zika."

There has been some speculation that Trump might tap Rubio as his running mate, but Rubio's refusal to walk back his sharp attack on Trump's fitness for the presidency makes a Trump-Rubio ticket untenable. The Republican National Convention will kick off just five weeks from now.