Senate Majority Leader Chuck Schumer (D-N.Y.) and Senate Minority Leader Mitch McConnell (R-Ky.) are at at loggerheads over a power-sharing arrangement in the 50-50 split upper chamber, with a rift over the filibuster rule keeping the two from reaching a deal on how to manage proceedings. Schumer and McConnell started talking earlier this week about a possible power-sharing deal governing daily operations, because even though Democrats have the majority in the Senate since Vice President Kamala Harris can cast a tie-breaking vote, she cannot be expected to take part in Senate proceedings every day to decide every dispute. As part of the negotiations around the power-sharing arrangement, McConnell has made a demand for a promise to protect the long-standing Senate rule requiring a supermajority of 60 votes to advance most legislation, known as the legislative filibuster. The rule protects the Senate from partisan control of the majority. Schumer is resisting McConnell’s request. …