LEESBURG, Va. — Vice President Joseph R. Biden Jr. delivered an emotional push for gun control measures that the administration is proposing at a House Democratic retreat here, saying recent tragedies leave lawmakers no choice but to act to mitigate the damage of future incidents.

The pep talk amounted to preaching to the choir. Most Democrats are supportive of some, if not all, of the measures.

“Enough is enough is enough,” Biden said. “Don’t tell me because we can’t solve it all we can’t act at all.”

Biden said the political landscape is far different today than in 1994, when Congress passed a ban on assault weapons, which some analysts said then contributed to significant losses in the midterm elections that year.

“The world has changed,” Biden said. “The American public has changed.”

The vice president said he met with 229 organizations in crafting a series of proposals that he presented to President Barack Obama and that those meetings demonstrated the political changes. Specifically, he cited that law enforcement groups were in support “across the board” unlike in 1994 and that religious organizations were surprisingly supportive of the proposals.

Obama is proposing to enact a stricter version of the assault weapons ban that passed in 1994 but lapsed 10 years later because of a sunset provision, restrict the number of bullets that magazines can hold, enact requirements for “universal” background checks for gun purchases and increase the availability of mental-health services.

Biden said the administration is strongly opposed to arming school officials but also that they are exploring offering federal assistance to allow localities to pay for “school resource officers” who might be armed.

The National Rifle Association, a politically powerful group that opposes new restrictions on guns, has proposed federal funding for armed guards at schools.

Biden said that while the proposals won’t entirely prevent future gun violence, they would mitigate the damage. He pointed to Rep. Ron Barber, a Democrat from Arizona in the audience who worked for former Rep. Gabrielle Giffords when she was shot at an event in her district in 2011, as a case in point that the number of bullets could make a difference in the amount of damage an assailant could commit at a mass shooting. Jared Lee Loughner, the shooter in that incident, was tackled as he attempted to reload his gun.

Biden also said he is planning a nationwide tour to promote the proposals, including in parts of the country where there is a “legitimate gun culture.”