Some supposed “moderates” are nervous It won’t make a difference: Senior House Republicans are moving swiftly to build a case against Homeland Security Secretary Alejandro Mayorkas as they strongly weigh launching rare impeachment proceedings against a Cabinet secretary, a plan that could generate sharp backlash from GOP moderates. Key committee chairmen are already preparing to hold hearings on the problems at the southern border, which Republicans say could serve as a prelude to an impeachment inquiry against Mayorkas. Three House committees – Oversight, Homeland Security and Judiciary – will soon hold hearings about the influx of migrants and security concerns at the border. The House Judiciary Committee, which would have jurisdiction over an impeachment resolution, is prepared to move ahead with formal proceedings if there appears to be a consensus within the GOP conference, according to a GOP source directly familiar with the matter. The first impeachment resolution introduced by House Republicans already has picked up support, including from a member of the GOP leadership team. A GOP source said the first Judiciary Committee hearing on the border could come later this month or early February. One top chairman is already sounding supportive of the move, a sign of how the idea of impeaching President Joe Biden’s Cabinet secretary has moved from the fringes to the mainstream of the conference. “If anybody is a prime candidate for impeachment in this town, it’s Mayorkas,” Rep. James Comer, chairman of the House Oversight Committee, told CNN. It’s exceedingly rare for a Cabinet secretary to be…