The nation’s principal law enforcement organizations, whose leaders testified and lobbied aggressively for the bill, also made great use of the booklets and Appendix A. In fact, it was a survey showing overwhelming support for an assault-weapons ban from police chiefs in and around his Congressional district that persuaded Representative Henry J. Hyde of Illinois, the top Republican on the House Judiciary Committee at the time, to support the bill. His surprise yes vote offset the no vote of the committee’s conservative chairman, Representative Jack Brooks, a Texas Democrat, so that the bill could move to the floor of the House.

The existence of Appendix A also made it possible for Senator Ben Nighthorse Campbell, a Colorado Democrat and longtime N.R.A. member — coupled with his own reaction to a torrent of gun-lobby phone calls — to commit to supporting Senator Feinstein’s bill if it was essential. That moment came when a motion to table, or effectively kill, the bill came before the Senate. Although the motion would have failed with a tie vote of 50 to 50, Senator Feinstein asked Senator Campbell for his vote to show that a majority of senators supported the bill. He honored his commitment, and the motion to table failed, 49 to 51, paving the way for the ultimate passage of the bill by a vote of 57 to 43.

Following the Newtown tragedy, inaction is not an option, morally or politically. President Obama and Vice President Joseph R. Biden Jr. (who championed the original assault-weapons ban when he served in the Senate) are on the right track with their plan to present legislation before the new Congress.

Preventing another slaughter will require not just new gun regulations, but also education, mental health care, greater access by law enforcement agencies to mental health records and assistance for parents, while respecting the whole Bill of Rights.

But the lesson from nearly two decades ago remains clear. If any meaningful change is to come, legislators must again devise a bill that both regulates assault weapons and respects and protects gun owners.

If we want to reimpose a permanent assault-weapons ban and restrict high capacity ammunition magazines, let’s include a new list of exempted rifles and shotguns used for recreational shooting in a new Appendix A (updated annually) and actively solicit input from the shooting community to make it work.

If we want to require background checks for all private sales at gun shows, let’s cap the cost so that private sales aren’t prohibitively expensive. Better yet, when we do this, let’s find an efficient way to allow individual sellers to directly use the same F.B.I.-managed background check system they must now pay federally licensed gun dealers to access for them.