WASHINGTON—The stock market ended the turbulent year of 2020 at all-time highs despite the coronavirus pandemic and resulting economic recession. With 2021 underway, the political events of the first week will set the tone for the new year as they have important implications for the political landscape and the markets going forward. The focus will be on the Georgia runoff elections on Jan. 5, which will determine control of the Senate and policies in Washington. Also, investors will closely watch the joint session of Congress on Jan. 6, which is expected to be “a very contentious meeting.” The new Senate currently stands at 50 Republicans and 48 Democrats. Should Democrats win both Georgia runoffs, this would put the balance at 50-50. If there’s a Biden administration, the Democrats will have control of the chamber because Kamala Harris as vice president would break any ties. Analysts, however, expect Republicans to hold on to the …