As the struggles in Congress appear to continue throughout the 111th Congress as it passes the first third of its second session [the 112th Congress will convene in January 2011 after this fall's elections] it must certainly be under consideration by the Obama Administration that the instaneous fix of issuance of Executive Orders becomes more appealing. There are legal studies and excellent analysis of the Executive Order function and its impact available but none are really recent. The most famous exercise of governance by Executive Order was when President Truman tried to seize the steel mills through an Executive Order during the Korean War. That effort was repudiated by SCOTUS and Justice Jackson raised the question and answered it negatively as to whether the President had any implied powers. That discourse and others of course is what led to the infamous DOJ/OLC opinions during the GWOT [Global War on Terror] which was a war never declared by Congress.
Perhaps as a present to each incoming President, NARA [the National Archives and Records Administration] should have completed an update and review and integration of all extant Executive Orders incorporating all changes issued or other modifications such as repeal by Congressional action [this has happened only once to my knowledge and involved an E.O. concerning the National Defense Stockpile function which was assigned by the President under Reorganization Plan No. 3 of 1978 and its implementing Executive Orders and then reassigned partially elsewhere in the fall of 1979 when FEMA had barely opened its doors]and Congress and FEMA were confused about what had happened. So Congress revoked the critical EO reassigning the functions and the President issued an entirely new order assigning the function management function to DOD. What FEMA did with 5 FTE DOD now does and has done so since 1980 with over 100 FTEs. Of course the theory does float around that FEMA was designed to house programs that the White House really wanted to be as dormant as possible, or is the correct word "doormat" meaning FEMA's role in the Executive Branch.
Back to substance however. President William Jefferson Clinton promulgated an Executive Order that mandated that replacement workers could NOT be hired when unionized employees went out on strike under federal contracts. That Executive Order was determined to be null and void and have been issued with no basis in law by the United States Court of Appeals for the District of Columbia. No petition for rehearing or request for certiorari was filed by the Clinton Administration, largely due to fear that the decision would be upheld and Presidential authority further delimited.
Of course to my mind the greatest exercise of an implied power by a President was President's acquisition of the Louisiana Territory so this saga is not yet done.
None the less, the Obama Administration could do a real service by having the one-time consolidated version of extant Executive Orders issued in 1989 as President Reagan left office updated. There is an Executive Order on Executive Orders which is EO 11030. It makes for an interesting read.
My point however will be summarized by the fact that three current Executive Orders, two of which have been amended cite the repealed/lapsed Federal Civil Defense Act of 1950, Public Law 920 of the 81st Congress as at least partial authority for their issuances. Whatever legal determines it seems at a minimum they should be reviewed formally to determine if this repeal has any significance on their structure or even existence. While I doubt any would be significantly compromised the search for new authority to cite, not just implied Presidential authority could prove quite interesting.