Thune and Johnson both plan to attend Trump's Dallas convention

House and Senate Republican leaders are heading to Dallas to embrace the president who has done the most to shape — and complicate — their political fortunes. Why it matters: Majority Leader John Thune and Speaker Mike Johnson don't have much of a choice about attending September's midterm convention. President Trump doesn't tolerate high-profile dissent, and both leaders know their best chance of staying in power is by staying united. But for Republicans in tight races, the two-day political…