From John D. Feerick and John Rogan at The Hill, an interesting piece on the 25th Amendment’s role in Nixon’s resignation:

Fifty years ago this week, Richard Nixon resigned from the presidency, and it might not have happened—at least not when it did—without the Constitution’s 25th Amendment and its vice presidential replacement procedure. That procedure allowed Nixon to appoint fellow Republican Gerald Ford to fill a vacancy in the vice presidency eight months prior. It ensured that Nixon’s resignation would result in Ford taking over the White House, instead of the Democratic Speaker of the House of Representatives, the next official in the line of succession. 

The prospect of a change in party control could have impacted Nixon’s decision to resign. It also could have altered the assessments of the Republican lawmakers and members of the public who turned on Nixon as his ties to the break-in at the Democratic National Committee’s Watergate Building headquarters were exposed. Even many congressional Democrats were hesitant to pursue Nixon’s removal when there was a vacancy in the vice presidency. They worried about the perception of stealing the White House. At the very least, the guarantee that partisan control would not shift helped minimize disruption and division at a tumultuous time for the nation.