As this exchange shows, Secretary Rumsfeld was not in the NMCC when the shootdown order was first conveyed.
( ( As ( ( this exchange ) shows ) ) ( , ( ( Secretary Rumsfeld ) ( ( ( ( was not ) ( in ( the NMCC ) ) ) ( when ( ( the ( shootdown order ) ) ( was ( first conveyed ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (DT this) (NN exchange)) (VP (VBZ shows)))) (, ,) (NP (NNP Secretary) (NNP Rumsfeld)) (VP (VBD was) (RB not) (PP (IN in) (NP (DT the) (NN NMCC))) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN shootdown) (NN order)) (VP (VBD was) (NP (JJ first) (NNS conveyed)))))) (. .)))
This is the main reason for the miscommunication.
( This ( ( is ( ( the ( main reason ) ) ( for ( the miscommunication ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (DT the) (JJ main) (NN reason)) (PP (IN for) (NP (DT the) (NN miscommunication))))) (. .)))