With the federal government getting closer to running out of cash to cover all bills on time, companies that evaluate bonds are having to consider how to rate America's creditworthiness.And their job didn't get any easier on Thursday when President Trump continued his attacks on congressional leaders over their failure to raise the federal debt ceiling.Other U.S. officials have been trying reassure the financial markets that no default is imminent.But in a morning tweet, Trump blamed the two top Republicans in Congress — House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell — for not attaching the debt-ceiling legislation to a popular bill on veterans' benefits. Whether that legislative strategy would have worked cannot be known. Further, attaching the debt ceiling to the veterans bill could have endangered one of the few legislative achievements Congress could claim in the midst of the GOP health care failure.In any case, Congress now has just a few more weeks to raise the debt ceiling, which would enable the government to continue borrowing enough cash to pay all of its bills on time. If it doesn't do so, the government will have to prioritize which of its bills it will pay. That would have enormous consequences in the financial markets.Ryan and McConnell have tried to send a message that a debt default is highly unlikely."We will pass legislation to make sure we pay our debts and we will not hit the debt ceiling. We'll do this before the debt ceiling," Ryan said during a visit to a Boeing plant in Washington state Thursday. "There are many different options in front of us on how we achieve that."Treasury Secretary Steve Mnuchin has offered similar assurances."We're going to get the debt ceiling passed," Mnuchin said Monday at an eventin Louisville, Ky. "Everybody understands this is not a Republican issue; this is not a Democrat issue. We need to be able to pay our debts."But Trump's attacks on Ryan and McConnell have raised questions about whether the passage of debt-ceiling legislation will be as smooth as congressional leaders hope.Under President Barack Obama, the White House and Congress often engaged in brinksmanship over whether to raise the debt ceiling, but they always managed to do so at the last minute."Clearly we've had dozens of occasions when the debt limit has been raised in the past, and we don't expect this time to be any different," says Charles Seville, senior director at Fitch Ratings.This time, however, the stakes are higher, said Richard Bernstein, former chief investment strategist at Merrill Lynch, in an interview with Politico: