Without even delving into the legal aspects of this response, the "Texas seeks the unprecedented step" part is an ad hominem and the mention of Trump's other lawsuits is a red herring.

It's also funny how many bullshit adjectives they managed to inject. "Texas seeks the unprecedented step of commandeering the electoral process of a separate and coequal sovereign state". Texas has made abundantly clear they are arguing that PA violated the Constitution with regards to how they handled the election. If PA is allowed to get away with this, they're not coequal as they have been granted a special privilege to violate whatever Constitutional requirements they find inconvenient.