WASHINGTON — The Republican Party’s capture of the House majority, though narrow, will soon transform the agenda in Washington, empowering GOP lawmakers to pursue conservative goals, vigorously challenge the policies of Democratic President Joe Biden — and plunge into Washington investigations with their new subpoena powers. Come next year, Republicans have made clear, the Democratic-led Jan. 6 investigative committee will be no more. Instead, public probes into the president’s son, Hunter Biden, will begin. And GOP priorities including border security, parents’ rights and major IRS cuts will be on fast tracks to the House floor. It’s a familiar whiplash, reminiscent...