That is what he has asserted after the fact, many, many times. Haig also said: everyone in that room knew what I was talking about.
http://en.wikipedia.org/wiki/United_States... Line of succession
The Cabinet is also important in the presidential line of succession, which determines an order in which Cabinet officers succeed to the office of the president following the death or resignation of the president. At the top of the order of succession are the Vice President, Speaker of the House and President pro tempore of the Senate, and Secretary of State. Because of this, it is common practice not to have the entire Cabinet in one location, even for ceremonial occasions like the State of the Union Address, where at least one Cabinet member does not attend. This person is the designated survivor, and he or she is held at a secure, undisclosed location, ready to take over if the President, Vice President, Speaker of the House, President pro tempore of the Senate, Secretary of State and the rest of the Cabinet are killed.