No good can come of the gov't trying to control what domains can be accessed, and it won't stop those that wish to do us harm or take advantage of us, because they'll just use another domain.
That's the wrong response though. It distinguishes between this bill and other internet-monitoring-and-censoring bills, when in reality none exists: all of them are equally silly due to technological reasons. Instead of saying that nothing good can come from the government controlling what domains are accessed (which is true), point out that it's technically impossible and makes us look like idiots.
What I wrote them was a little more in depth and more general, but I think it is important to mention the specific bill each time in addition to the overall sentiment, so the secretary reading the mail puts an X mark in the tally next to the bill number on her notepad. :)
Basically, I pointed out that things have been just fine with the free uncensored net we've had so far, that this would limit that freedom by attempting to restrict what we could visit, and that those with malicious intent could easily thwart such attempts.
I think that part of the reason they are doing this is to attempt to have access to block off our country's network in case of "cyberwar", etc., so it is probably a defensive measure, rather than what they claim it to be. They probably can't just do this type of blocking at the periphery, since satellite, etc. connections within the U.S. could just as easily be a danger, not just the big trunks coming out of the ocean.
I don't want our country to be at risk, but I think that a simple blacklist is not the way to do it. Now, if they installed devices at each ISP that all traffic had to run through- then you might have a greater defense. But, basically, in cyberwar, we're all screwed. Things like this are chump change compared to EMPs, viruses, state-controlled botnets, etc. Cyberwar would be almost purely offensive, similar to nuclear war.