I think McCarthy set it up where Johnson would play conservative, play up to Trump and get his support by pretending to be pro Border security and anti-Ukraine funding. Once in he continued to be pro-Trump until he made his move to do a complete turnaround thus betraying his Border border America first vows. This now puts Trump on the spot on whether he will continue to support Johnson or disavow him publicly.
Meant pro-border America first vows.
Sadly that ship has sailed since Trump met and posed with Johnson just a few days ago to directly endorse Ukraine aid. Completely ignoring the border.