Supporters and opponents of a bill banning military-style assault weapons debated the merits of once again banning the weapons at an emotionally charged hearing Wednesday, even though senators acknowledge that the proposal lacks the support necessary to pass the closely-divided Senate.

Sen. Dianne Feinstein (D-Calif.) stands next to a display of assault weapons during a news conference in January on Capitol Hill. (Alex Wong/Getty Images)

In the most dramatic exchange, the father of a 6-year-old boy killed in the mass shooting at Sandy Hook Elementary School in Newtown, Conn., wept openly and showed pictures of his son as he urged senators to reinstate the ban.

Neil Heslin recalled that on the day of the shooting, Dec. 14, he took his son, Jesse Lewis, to a local diner where they ordered the child's normal breakfast sandwich of sausage, egg and cheese and a hot chocolate.

As Jesse said good-bye to his father outside the school, Heslin said, Jesse told him, "It's going to be okay."