New York City Mayor Michael Bloomberg waits to speak at a gun violence summit at Johns Hopkins Bloomberg School of Public Health in Baltimore on Monday, Jan. 14, where he outlined his proposals for federal gun control reforms. (Patrick Semansky/AP)

New York Mayor Michael R. Bloomberg (I) brought his nationwide campaign for stricter gun control to Baltimore on Monday, imploring President Obama and lawmakers on Capitol Hill to summon the will to put in place meaningful reforms to reduce gun violence in the country.

“This is not a constitutional question; it’s a question of political courage,” Bloomberg told a crowd gathered for a two-day gun summit at Johns Hopkins University’s public health school, which bears the mayor’s name. “The rate of firearms homicide in America is 20 times higher than it is in other economically advanced nations. We have got to change that, and it has to start this week with real leadership from the White House.

In a 20-minute speech that came exactly one month after a school massacre in Newtown, Conn., Bloomberg pointed to a new report from Mayors Against Illegal Guns — an organization he helped found in 2006 and co-chairs — that highlights the lack of firearms-related research that advocates say is essential to helping lawmakers craft better public policy.

The report details intense efforts by the National Rifle Association over the years to limit such data, often with marked success — for example, pushing for a provision in Obama’s health-care bill to restrict doctors’ ability to gather data about their patients’ gun use and supporting restricted funding for gun-related scientific research.

Bloomberg exhorted lawmakers in Washington to get out of the way of legitimate research on real public health issues such as gun violence.

“Congress has no business dictating what public health issues scientists can and can’t study. What are they afraid of?” Bloomberg said. “When elected officials try to muzzle scientific research and bury the truth, they make our society less free. . . . It’s time for Congress and the White House to put public health above special-interest politics.”

Officials at Johns Hopkins organized the two-day summit in response to the Newtown shootings, piecing together a long list of academics and activists to examine many facets of firearms in the United States, including weaknesses in the system of background checks and an examination of how federal policy on gun ownership has changed over time. The sessions include case studies of how other countries have acted after deadly shootings in an effort to reduce gun violence.

Bloomberg has long advocated stricter gun controls, particularly a more stringent background-check system that is free of loopholes.

He has been ubiquitous since last month’s shootings at Sandy Hook Elementary School, where a gunman killed 20 students and six adults. From news conferences in New York to an appearance on NBC’s “Meet the Press,” he has implored Obama to “use whatever powers his office holds to address this violence” and has insisted that lawmakers in Washington make new gun legislation their “first order of business” in the new year.

Among the measures Bloomberg has advocated, which he repeated Monday: a ban on the manufacture and sale of military-style assault weapons; more robust background checks for potential gun owners; and stiffer penalties for firearm traffickers.

Bloomberg also said the Obama administration could make a handful of immediate changes without the need for legislation. He urged the president to order all federal agencies to submit relevant data to help fill out the national background database; to make a recess appointment for a new head of the Bureau of Alcohol, Tobacco, Firearms and Explosives; and to instruct the Justice Department to make a priority of convicting criminals who lie on background checks.

Maryland Gov. Martin O’Malley (D), speaking before Bloomberg on Monday, said he expects the introduction of a bill in the state legislature this week that would put in place a range of new measures. Like Bloomberg, he said the goal is not to prohibit guns altogether but rather to put in place a set of “common sense” reforms.

O’Malley said the legislation would improve background checks, ban military-style assault weapons, limit the size of ammunition magazines, improve mental health services and heighten security at schools.

“There is a sickness in our country, and that sickness is gun violence,” O’Malley said. “These are human problems, and so, too, are their solutions.”