TAMPA ­— President Obama is tapping Senator John F. Kerry to deliver a speech focused on national security issues during the closing night of next week’s Democratic National Convention.

The three-day gathering in Charlotte, N.C., will have a heavy national security focus, underscoring the administration’s intention to highlight its work to end combat operations in Iraq, draw down forces in Afghanistan, and approve a military raid that killed Osama bin Laden and contrast these accomplishments with the rhetoric of Republican nominee Mitt Romney.

Kerry is chairman of the Senate Foreign Relations Committee and has served as an unofficial administration envoy to trouble spots in the Middle East, Horn of Africa, and Afghanistan.

Kerry also is a potential secretary of state if Obama wins reelection. He has been poring over Romney’s record in preparation for his role as the former Massachusetts governor’s stand-in during Obama’s debate preparation sessions.