Relentless single-mindedness on the economy: as president, Clinton rode the catchy “It’s the economy, stupid” wave into the White House and made it a central part of his administration throughout his eight years in office.
Regardless of what else transpired during Clinton’s administration, including the Monica Lewinsky scandal and subsequent impeachment debacle, Republicans were never able to dent his armor on the economy. And, in the end, that’s mostly what the public cared about.