The Republican-aligned opposition research group America Rising is doing all it can to prevent President Biden from seating his top Cabinet picks.Why it matters: After former President Trump inhibited the transition, Biden is hoping the Republican minority in Congress will cooperate with getting his team in place. Biden hadn't even been sworn in when America Rising began blasting opposition research to reporters targeting Janet Yellen and Alejandro Mayorkas.Get smarter, faster with the news CEOs, entrepreneurs and top politicians read. Sign up for Axios Newsletters here.Biden’s reliance on officials who have previously served in government, many in the Obama administration, has provided a wealth of research material, according to America Rising's leaders. * The group currently has 15 researchers, trackers and communications operatives digging into the people who would serve in Biden's administration, with plans to expand in the near future. * It's already filed more than 300 FOIA requests for Obama-era records involving holdovers expected to serve in Biden’s government.This week, America Rising dredged up past controversies involving Mayorkas, Biden’s pick to lead the Department of Homeland Security, during his stints in the Clinton and Obama administrations. * And when Yellen, who is vying to lead the Treasury Department, said during a hearing Tuesday that raising the minimum wage would result in negligible job losses, America Rising quickly sent out a 2014 clip of her predicting more dire economic consequences. * Whether they can succeed in blocking — or even holding up — many of Biden's picks is a separate question. The president's first Cabinet nominee, Avril Haines as director of national intelligence, was confirmed hours after Biden was sworn in. And Yellen's Tuesday hearing was largely uneventful.What we’re hearing: During an interview Tuesday, the group's executive director Cassie Smedile and communications director Chris Martin spelled out its strategy and tactics heading into the Biden administration. * “America Rising’s work during the presidential campaign never stopped,” Martin said. * Smedile said: “We think it’s important to keep a focus on the people who are going to be running our government."Be smart: The Biden team’s reliance on former Obama officials to staff its upper ranks means bringing in some big names who went through the revolving door from government service to the private sector, and now back again. * This provides opportunities for conflicts of interest, which, from America Rising’s perspective, means a lot of research fodder.Support safe, smart, sane journalism. Sign up for Axios Newsletters here.