There was broad bi-partisan support for the first Gulf War (response to Iraq invading Kuwait) and the war in Afghanistan (response to 9/11).

The broader dissent started to come after the invasion of Iraq (based on the notion of Iraqi WMDs) and the lack of progress in Afghanistan or finding Bin Laden.

Foreign policy under different Presidents is often contradictory and as in any political context, the President usually has some base of support from their own party no matter how far off script they go, simply out of unity or fear of the alternative party benefiting from a lack of unity.

So while a coherent policy of “The US should intervene in all conflicts or no conflicts” would be intellectually consistent, the circumstances surrounding the conflict and the political environment lead to inconsistencies.