OTTAWA—The conditions for a brawl appear to be set after Government House Leader Pablo Rodriguez announced that he will testify at a parliamentary committee about the now-dead WE deal on Monday, rather than Prime Minister Justin Trudeau or members of his staff. In a letter to the chair of the House of Commons ethics committee on Sunday, Rodriguez said that one of Trudeau’s senior advisers had been instructed not to appear before the committee—and that he will be attending in his place. “Staff are not elected members of the House, they do not have the same rights and privileges as MPs. Calling staff to testify at committee is at odds with the long-standing principle of ministerial responsibility,” Rodriguez said in a letter to committee chair Chris Warkentin. “Accordingly, Mr. Rick Theis, director of policy to the prime minister, has been instructed to not appear before the committee. In his place, …