So let's say Gore won. It could have happened.
President Gore takes the warnings from the CIA seriously. He doubles security at the airports, 9/11 never happens. Nobody knows how bad 9/11 could have been. The Republicans scream about the increased security at the airports, calling it a waste of money and an attack on individual liberty.
Next, since there was no 9/11, President Gore has more resources to investigate the financial sector. He heeds the warnings of Brooksley Born. By raising interest rates and thanks to the SEC and FBI the financial sectors shenanigans are diverted and the housing bubble doesn't happen. Nobody knows how bad the economic crash could have been. The Republicans scream about government interference in business.
So after four years of President Gore, the nation and world are about 100 times better off than what really went down. Then President Gore loses his reelection bid. The Republicans win on a platform of "More Liberty" and "Less Government" and "No Nanny State". Al Gore goes off to Jimmy Carter Land.
The scariest thing about this scenario is that many politicians know it to be true. That it's better to be reactive than proactive. Something to think about when you're wondering why our leaders do what they do. It could have happened.