• Political Strategist Karl Frisch of Bullfight Strategies calls in at 9am ET / 6am PT to talk about gun control, and about this week’s terrorism in America

Lanny DavisLanny Davis, veteran political strategist and former White House special counsel to President Clinton, calls in at 10am ET / 7am PT to talk about his book “Crisis Tales: Five Rules for Coping with Crisis in Business, Politics, and Life”

Mark Follman from Mother Jones calls in at 11:30am ET / 8:30am PT to discuss debunking NRA myths about more guns mean safer schools

Rescue workers searched rubble early today for survivors of a fertilizer plant explosion in a small Texas town that killed as many as 15 people and injured more than 160 others. The blast left the factory a smoldering ruin and leveled homes and businesses for blocks in every direction.

• President Obama and gun control allies say Senate rejection of expanded background checks and other restrictions won’t stop the drive to reduce gun violence.

Federal agents on Wednesday arrested a suspect in the mailing of letters to President Barack Obama and a U.S. senator that initially tested positive for the poison ricin. The suspect was identified as Paul Kevin Curtis of Tupelo, Miss.

A service in Boston to honor the victims of the city’s bombings will be attended by President Obama today, as investigators spend a third day combing through evidence in search of those responsible for the deadly blasts.