Senate Democrats on Tuesday closed ranks behind Secretary of Health and Human Services Kathleen Sebelius, declaring she should keep her job despite problems plaguing the Affordable Care Act’s insurance exchanges. Democrats sought to deflect criticism by Republicans who have called for Sebelius’s ouster over what even Democrats acknowledge has been a botched rollout of the landmark law. Sen. Jay Rockefeller (D-W.Va.), the chairman of the Senate Commerce Committee, praised the implementation of ObamaCare for proceeding smoothly compared to other massive federal programs. “If you compare it to all kinds of other programs of large magnitude, it’s actually ahead of schedule,...