Not necessarily less isolationist, tho I cant entirely discount that possibilty. What I am describing is reforming the War Dept & Army, and sinking funds into something akin to CoS Marsh proposals. From the Spanish American War the US had developed a series of war plans for dealing with overseas wars. At the stratigic level the War & Navy Departments had a understanding of what it would take to execute the "Color Plans". What we can see from comparing these plans of 1902-1940 is Congress never took the Army portion of them seriously and almost nothing required to execute the Army portion of these plans was funded or organized. The Navy was in much better shape in this & as it stood had some ability to execute its part in the larger war plans like Orange (Japan), Yellow (China), Green (Mexico), Blue (defense of the continental US).
The US public was ok with funding a large Navy, they even demanded it & were harsh on politicians who opposed it. Conversely the fiscal conservatives that dominated the US Congress for these decades were able to squelch any proposal to create a Army comparable to the Navy. One of the reasons the Navy was able to win the budgetary and doctrinal battles for expanding its Marine Corps from a ships guard to a combined arms expeditionary force of 20,000 regulars and 8,000 reservists was the inability of the Army to provide such a standing force with the budget it had.
For informational purposes here is a brief sketch of the Marsh plan for a 20th Century US Army. Submitted to the Sec War in 1919.
500,000 Regular army standing force. This would comprise both field forces and a robust schools staff for training reservists & new recruits at the start of a war mobilization.
500,000 National Guard made up from the former states militias. These would be fully equipped as a field force of infantry divisions & receive Regular army supervised training. Marsh recommended a 1,000,000 man NG, but the proposal was reduced.
100,000+ Trained Reserve officers. These would be officers drawn from a reserve training program among civilian college & university students, and regular army officers leaving army service. These would be seperate from the National Guard & Regular Army OB, comprising 2,500 man 'division' officer cadres and a group for supplementing school staffs.
Industrial planning board and subsidies for industry retaining a reserve weapons manufactoring capacity. That is the ability to shift to weapons/equipment production in pace with training a mass of new recruits. This included a robust R & D budget.
Goal of all this was the ability to field a expeditionary force of 100,000 imeadiatly, 500,000 men in six months, 1,000,000+ in 12 months. As it was the Army was hard pressed to provide a understrength 15th Infantry Regiment for deployment in the Shanghai emergency in 1927. The Navy had a Expeditionary Brigade of 4,000+ embarked in less than two weeks. When the war scare of 1937 over the sinking of the gunboat Panay came the Sec War was embarassed to report the Army could not deploy 20,000 organized and armed men to the west coast in less than 60 days.