Some of Joe Biden’s supporters are voicing growing concern that his campaign is not prepared to weather the dual political rip currents suddenly reshaping the 2020 race — an onslaught of attacks on his family from President Trump and a tightened contest for the Democratic nomination.

Several allies, including top financial backers, are weighing whether to create a super PAC to independently defend Biden and go after the president, who has repeatedly accused the former vice president of corruption and whose campaign last week launched a $10 million ad blitz aimed largely at attacking Biden.

Other supporters caution that a more aggressive approach could cut against Biden’s above-the-fray appeal and warn him against losing sight of Sen. Elizabeth Warren (D-Mass.), whose steady march in popularity has eroded Biden’s standing and given her narrow leads over him in several recent polls in early-voting states.

“I do think things have changed. . . . You have to recalibrate based on the fact that Trump’s attacks on you are going to be at the center of these impeachment hearings,” said Larry Rasky, a longtime ally of Biden who had senior roles in his two previous presidential campaigns. Rasky said he worries Biden’s campaign has been naive about the amount of resources needed to counter Trump.