House Speaker Nancy Pelosi, D-Calif., holds a press conference with former Rep. Gabrielle Giffords, left, and Rep. Mike Thompson, D-Calif., to introduce legislation on expanding background checks for gun sales at the Capitol in Washington, D.C., Tuesday.

House Speaker Nancy Pelosi, D-Calif., holds a press conference with former Rep. Gabrielle Giffords, left, and Rep. Mike Thompson, D-Calif., to introduce legislation on expanding background checks for gun sales at the Capitol in Washington, D.C., Tuesday.

House Speaker Nancy Pelosi, D-Calif., holds a press conference with former Rep. Gabrielle Giffords, left, and Rep. Mike Thompson, D-Calif., to introduce legislation on expanding background checks for gun sales at the Capitol in Washington, D.C., Tuesday.

House Speaker Nancy Pelosi, D-Calif., holds a press conference with former Rep. Gabrielle Giffords, left, and Rep. Mike Thompson, D-Calif., to introduce legislation on expanding background checks for gun sales at the Capitol in Washington, D.C., Tuesday.