Mr. Biden is now confronting a series of challenges: a third-quarter fund-raising haul that fell well behind the totals of Ms. Warren and Senator Bernie Sanders of Vermont; struggles in some early state polls; and scrutiny on his family after revelations that President Trump asked the Ukrainian government to investigate Mr. Biden and his son Hunter.
There is no evidence that Mr. Biden, as vice president, acted improperly to aid his son’s overseas business dealings, but the development has emerged as a major distraction to his campaign message at the same time he has been slipping in the polls. –
On Wednesday, Mr. Biden again sought to put the controversy behind him, repeatedly working to bring the focus back to Mr. Trump and casting him as dangerous and corrupt.
“Mr. President, release your tax returns or shut up,” he said at one point, looking directly into the assembled cameras.
And Mr. Biden, who often talks about civility, appeared far more eager to seize opportunities to tweak his Democratic rivals than he has on many previous occasions.
“God love Bernie, you know it was really good, I really mean it, to see him so healthy and moving last night,” Mr. Biden said of Mr. Sanders, who recently suffered a heart attack. “But Bernie! Bernie doesn’t pay for half his plan.”
Later Wednesday, Mr. Biden plans to give a foreign policy address in Iowa. Asked about Ms. Warren’s remark at the debate that the United States should “get out of the Middle East,” Mr. Biden, a former chairman of the Senate Foreign Relations Committee, embraced the chance to attempt to draw another contrast.