What is supersessionism?

Supersessionism is the Catholic doctrine that the Mosaic covenant ended and was replaced by the New Covenant in Christ. Dual-covenant theology, which teaches that Jews remain saved under the Mosaic Law, is false. Attempts in modern Catholicism (for example, the 2006 U.S. Catechism edition) to teach that the Mosaic covenant is “eternally valid” were corrected in 2008 after Vatican review and approval by the CDF in 2009.