Before there was Jed...
This is basically my headcanon for how the backstory of the West Wing happened. I may do more in the future.
With the failure of the 20th Amendment, this left President Nixon in a bind. Agnew had resigned, leaving him without a vice-president. And with Watergate becoming known to the public, Nixon's advisers suggested that his best course of action was to resign before any further damage was caused. Nixon heeded the advice, and announced his resignation in a televised address to the country in early 1974.
"Tomorrow, at 12:00pm, I will resign, effective immediately, from the office of the presidency. Speaker Albert will become president, and I ask you all that you give him the utmost support during this time."
It was official. Speaker of the House Carl Albert ascended to the presidency and got to work immediately. In his State of the Union, he called upon Congress to adhere to the will of the people and set a new election for that November. He also urged Congress to enact a new amendment that allowed for the president to appoint a vice-president in the case of vacancy. With overwhelming public support, both initiatives easily passed. Albert then appointed Wisconsin Governor Patrick Lucey as his vice-president, and he was confirmed with little trouble.
With the election underway, there was little time to campaign. Albert was essentially assured the Democratic nomination, but he faced intra-party opposition from Georgia Governor Jimmy Carter and Connecticut Congresswoman Ella Grasso. At the convention, he easily prevailed, though not after Carter and Grasso extracted some concessions.
Meanwhile, the Republican field was wide open. The early frontrunners were California Governor Ronald Reagan and House Minority Leader Gerald Ford. Reagan caught fire quickly, referring back to his speech at the 1964 Republican convention. He became the conservative standard bearer that year, and this allowed him to outmaneuver the more establishment-flavored Ford. By the time of the convention, Reagan had a healthy lead in delegates. However, in order to soothe over any wounds that may have been inflicted in the primaries, he selected Ford as his running mate.
However, this year would not belong to Reagan. The entire Republican Party was cast in a pall thanks to Watergate, and it looked to be a Democratic year. Though the economy was weakening, it was widely understood that it was due to Nixon rather than Albert. While Reagan kept the race interesting and gave lively debate performances, it was not enough to escape the blue wave that November. On election day, President Albert secured a comfortable victory, almost completely turning around the catastrophic results of two years prior. Reagan's conservatism even turned off moderate suburban voters in traditionally Republican states like New Jersey and Illinois. The Democrats also gained strongly downballot, with the new presidential election season providing a boon to Democratic turnout in what would otherwise be midterm elections.