Was legitimising

"Meanwhile, Austria avoids equivalent censure despite the far-right Freedom party joining its ruling coalition last month. When the same party, whose roots go back to the Nazi apparatus, joined the government in 2000, Vienna was ostracised by fellow EU members. The charge was legitimising extremism. The Freedom party was then beyond the pale. The pale has moved." (The Guardian.)

Is "legitimising extremism" a complement and "was" a linking verb in The charge was legitimising extremism?