I really do think that Obama is busily replacing senior officers with people he can be sure will be loyal to him, and who in turn can be counted on to sniff out people junior to them who are "politically unreliable".
If a next Republican president attempts to undo this, and remove the Leftists in the military, the press will suddenly screech about "McCarthyism!"
I heard on the local radio news that 20 some odd high ranking officers have been replaced so far in the last year. Has this ever happened to the US during peacetime?