A paraphrased description of the brief states that it concludes that:
[T]he current [U.S. Navy] strategy . . . is based on maintaining carrier strike groups in the western Pacific and the Arabian Gulf, to counter China and Iran, along with global presence patrols and patrolling the maritime commons.
This strategy is driven by the distribution of naval power today. Only a handful of countries that the U.S. has any plausible possibility of being in a military conflict with have significant naval forces: China (62 submarines, including a few with more than coastal range, and 28 destroyers), North Korea (63 submarines, all coastal), Russia (67 submarines, many global in range, 15 destroyers, 5 cruisers and 1 aircraft carrier), Iran (9 submarines and legions of small missile boats), Turkey (14 coastal submarines), Pakistan (8 coastal submarines), Egypt (4 coastal submarines and a destroyer) and Vietnam (2 coastal submarines).
Every other naval power in the world is either an entirely reliable U.S. ally, or has a "frigate navy" with no submarines, and no surface warships larger than a frigate (e.g. a destroyer, cruiser or aircraft carrier), and most of those frigate navies are both small in terms of the number of ships involved and have less than state of the art naval technology.
China, North Korea and Vietnam, as well as part of the Russian fleet, are all in the Western Pacific. Both North Korea and China have rattled sabres in plausible ways in the recent past. North Korea has fired test missiles, tested nuclear weapons, apparently planted a sea mine that recently destroyed a South Korean naval ship, captured U.S. individuals and in generally taken a bellicose stance towards the world. China has repeated asserted claims to Taiwan, is developing a more sophisticated naval force, and has had threatening encounters that didn't reach weapons fire with Japanese and U.S. ships. Vietnam might feel compelled to be an ally to China in a war with the U.S.
Turkey is a NATO member and confined to the Mediterranean, which is home to many EU nations with substantial naval power and to our military ally Israel. Egypt's navy, should it prove to be hostile, is outmatched by our allies in the Mediterranean, subject to aircraft launched from the Aviano, Italy Air Force base, and it more likely to be working in a common cause with U.S. interests in the Red Sea. Egypt's coastal submarines would be hard pressed to make it to the Persian Gulf and sustain themselves undetected.
But, Iran's submarines and missile boats and cruise missiles pose a real threat to critical oil shipping that it has demonstrated in the past. So, the need to address this military threat is real.
But, what if budgetary constraints make it necessary to shrink the U.S. Navy's fleet which is by far the largest in the world. With a smaller fleet the U.S. Navy would:
have to give up many amphibs and smaller LCS vessels, along with many engagement and low end missions such as counter piracy [or] . . .
emphasize low end missions, buying lots of smaller LCS and corvette sized vessels to maintain a larger fleet, but it will be forced to give up high end carriers and other costly large surface warships [or] . . .
maintai[n] strong carrier strike groups and other surface warfare ships forward in the western Pacific while drawing down the presence in the Gulf. This option would also allow lower end engagement missions and patrolling the global commons.
The last solution may be the best one. A U.S. aircraft carrier group in the Persian Gulf may no longer be necessary.
What is the alternative?
There is a very good chance that the U.S. could now secure a permanent Air Force base in the region similar to those in Aviano, Italy or Okinawa, Japan, and will have something like 50,000 U.S. troops in Iraq for the foreseeable future in any case. In the past, this might have been seen as a threat to Iraq or other Arab states. Now, it would be seen merely as a precaution against Iranian military action that would disrupt the oil trade in the Persian Gulf.
It wouldn't take a very large Air Force base to have superior capabilities to an aircraft carrier, and this kind of base could also be home to the Navy's land based P-8 anti-submarine warfare aircraft. Some smaller U.S. Navy ships might still remain in the Persian Gulf, but freed of force protection for an aircraft carrier as a primary mission, far fewer navy surface ships would be required.
Also, so long as the U.S. had a reliable base in the region, it wouldn't have to have a full contingent of aircraft on hand at all times. It could have fewer planes on the ground during periods of detente, and could move in more on a couple of days notice when tensions increased, providing a much quicker ability to mobilize forces than a naval ship.
If there is just one region where the U.S. routinely needs to deploy its aircraft carrier fleet, instead of two, the U.S. Navy can do its duty in the West Pacific and globally, with a smaller fleet.
Each aircraft carrier group and associated fleet costs something on the order of $30-40 billion to buy before considering the cost of aircraft, and more each year to maintain. So, reducing the number of aircraft carriers the U.S. needs greatly reduces the procurement burden on the U.S. military, and does so even more in the short term as we shrink that fleet simply by not fully replacing it.