Lieberman may be right. But would it make any difference whether there is a Republican or a Democrat in the White House?
In 1993, a Democrat with no military experience (Clinton) was president and terrorists hit the WTC. In 2001, a Republican with some military experience (GW Bush) was in the White House and terrorists destroyed the WTC. Doesn’t seem to make much difference which party holds the presidency.
The response makes a difference. In 1993, the response was to arrest some people and consider it a law enforcement problem. In 2001, the response was to take out two State sponsors of terror (Iraq and Afghanistan), and bring to heel two more (Lybia and Pakistan).