Senate Democratic aides said that unlike debates in recent years on health-care reform and fiscal policy, Reid is likely to step back on the gun issue, allowing longtime gun control advocates, including Sens. Patrick J. Leahy (D-Vt.), Dianne Feinstein (D-Calif.), Charles E. Schumer (D-N.Y.) and Frank Lautenberg (D-N.J.), to steer legislation to consideration by the full Senate.