Well as far as the two front war senerio goes, lets look at some numbers.
US military intervention in Iraq at most will have 250,000 troops involved from all four services and the reserves.
Total number of US personal on active duty and in the reserves is 2.6 million. I should mention though that most of the 250,000 troops going to Iraq and most of the 2.6 million personal serving in the military are not "trigger pullers" or combat troops. Most are support personal who are vital to maintaining and supporting soldiers in combat. Without them it would be impossible to fight a war even for an hour!
War in Iraq in terms of ground combat troops will at most involve 4 US Army divisions and 1 Marine MEF.
A defensive war against North Korea will involve 3 US Army Divisions and perhaps another Marine MEF.
There are a total of 10 US Army Divisions and 3 Marine MEFS on active Duty. The US Army National Guard and Reserve have another 10 divisions in addition to non-attached smaller Brigades and Battalions. There is also 1 Marine MEF in the Marine reserve.
But remember many reserve combat units after they are mobilize often require extensive training lasting months before they are considered combat ready. But depending on the circumstances they could be deployed without that training, but that would only be done in the most extreme situations. Support personal due to the different nature of their job are ready to go help the active force at a moments notice.
The US Airforce and Navy are the largest in the world and in terms of combat aircraft dwarf the number of Aircraft that North Korea and Iraq have. Both North Korea and Iraq do not have Naval forces of significant size. Right now it looks like any war in Iraq will involve about 1,000 Airforce, Naval, and Marine Combat Aircraft. Thats only 25% of the total number of combat aircraft the USA has.
In the North Korea vs. South Korea situation, realize that while North Korea has a Military of 1.1 million that South Korea has a military of 700,000. South Korea in general has 60 to 70% of the equipment the North does and generally has better equipment and better training as well.
The problem with North Korea(besides having a couple of nuclear weapons) is the foward positioning of so many of their troops, nearly 70%, within 30 miles of the DMZ. North Korea has artillery built into the side of Mountains and protected by large concrete doors. North Korea has one of the largest inventories of Artillery in the world. With Seoul South Korea less than 30 miles from the DMZ, it is speculated that North Korea could fire up to 200,000 high explosive shells on to Seoul during the first day of combat. This is what most people worry about rather than the North Korean Military's ability to conduct a deep offensive into South Korea. Taking out that Artillery can be done, but not before there could potentially be massive loss of life in Seoul. I wish they had rebuilt Seoul further south of the DMZ after the Korean War, say 100 miles so it would be out of range of North Korean Artillery.
The USA does have enough forces to combat North Korea and Iraq, fight the war on terror, and if need be defend Tawain from a Chinese invasion. Remember, Chinese invasion of Tawain is dependent on Chinese Navy and Chinese sea lift and air lift which are small.
US military intervention in Iraq at most will have 250,000 troops involved from all four services and the reserves.
Total number of US personal on active duty and in the reserves is 2.6 million. I should mention though that most of the 250,000 troops going to Iraq and most of the 2.6 million personal serving in the military are not "trigger pullers" or combat troops. Most are support personal who are vital to maintaining and supporting soldiers in combat. Without them it would be impossible to fight a war even for an hour!
War in Iraq in terms of ground combat troops will at most involve 4 US Army divisions and 1 Marine MEF.
A defensive war against North Korea will involve 3 US Army Divisions and perhaps another Marine MEF.
There are a total of 10 US Army Divisions and 3 Marine MEFS on active Duty. The US Army National Guard and Reserve have another 10 divisions in addition to non-attached smaller Brigades and Battalions. There is also 1 Marine MEF in the Marine reserve.
But remember many reserve combat units after they are mobilize often require extensive training lasting months before they are considered combat ready. But depending on the circumstances they could be deployed without that training, but that would only be done in the most extreme situations. Support personal due to the different nature of their job are ready to go help the active force at a moments notice.
The US Airforce and Navy are the largest in the world and in terms of combat aircraft dwarf the number of Aircraft that North Korea and Iraq have. Both North Korea and Iraq do not have Naval forces of significant size. Right now it looks like any war in Iraq will involve about 1,000 Airforce, Naval, and Marine Combat Aircraft. Thats only 25% of the total number of combat aircraft the USA has.
In the North Korea vs. South Korea situation, realize that while North Korea has a Military of 1.1 million that South Korea has a military of 700,000. South Korea in general has 60 to 70% of the equipment the North does and generally has better equipment and better training as well.
The problem with North Korea(besides having a couple of nuclear weapons) is the foward positioning of so many of their troops, nearly 70%, within 30 miles of the DMZ. North Korea has artillery built into the side of Mountains and protected by large concrete doors. North Korea has one of the largest inventories of Artillery in the world. With Seoul South Korea less than 30 miles from the DMZ, it is speculated that North Korea could fire up to 200,000 high explosive shells on to Seoul during the first day of combat. This is what most people worry about rather than the North Korean Military's ability to conduct a deep offensive into South Korea. Taking out that Artillery can be done, but not before there could potentially be massive loss of life in Seoul. I wish they had rebuilt Seoul further south of the DMZ after the Korean War, say 100 miles so it would be out of range of North Korean Artillery.
The USA does have enough forces to combat North Korea and Iraq, fight the war on terror, and if need be defend Tawain from a Chinese invasion. Remember, Chinese invasion of Tawain is dependent on Chinese Navy and Chinese sea lift and air lift which are small.