Two key senators expressed optimism Sunday that Congress could strike a deal on expanding background checks for gun sales in the wake of recent, high-profile mass shootings this month. But Sen. Pat Toomey, R-Pa., warned that recent legislation passed by the House is a nonstarter in the Senate among Republicans and some moderate Democrats, arguing that the best way to find compromise is through measures that will require background checks on all commercial gun sales, including on the internet and at gun shows.

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