Native speakers of English, could you help me with my English?

I am translating a very complex book about architecture (this chapter is about famous architect Mies van der Rohe ) and there are phrases that I find difficult to understand. What does the following phrase mean 'could but barely reflect'? (does it mean the same as "could ONLY barely reflect'?) Here is the context:


Thus, where the School of Social Services with its centralized library to the rear permitted a more or less direct transposition of the portico entry and rotunda of the Altes Museum, Crown Hall could but barely reflect these constituent elements and then only at the expense of the programme.