It’s good practice for teams, businesses, and even political parties to learn as much from failure as they do from success. That was the principle Republicans applied after losing the White House in 2012, when under the leadership of Chairman Reince Priebus, the Republican National Committee launched the Growth and Opportunity Project to study how the party could be more competitive. In the 2014 midterm elections two years later, that study and the changes Chairman Priebus implemented as a result paid off in spectacular fashion. At every level from state legislatures to the Congress, the Republican Party is today objectively the strongest it has been in generations.

After the victories of 2014 and 2015, Chairman Priebus understood that the inverse of the old adage is true as well–the party has a duty to learn as much from success as it does from failure. I was honored when he asked me to lead a project to surface the “lessons learned” from these campaigns. Our report, released this week, is the result of dozens of interviews with candidates, campaign managers, and campaign staff for Senate, House, and governors’ races across the country.

The more we learned, the more we were struck with the scale of the changes Republican candidates are navigating–changes in the political environment, in the technology and tactics of campaigns, and in the strategies required to win.

Perhaps the most historic and underappreciated of these changes is the political realignment that has taken place over the past eight years.