Mike Johnson is trying to avoid the mistakes of his predecessor as he faces the toughest test of his political career on Friday. With his bid to keep his speakership on the line — despite support from President-elect Donald Trump — the Louisiana Republican is looking to sidestep the kinds of side deals with conservative Republicans that ultimately cost Kevin McCarthy his own political future. But that’s a hard tightrope to cross. Fiscal hawks want Johnson to make commitments, including...