AXIOS (Andrew Solender) - Trump looms large over Republican congressional primaries
President Trump will not be on the ballot this year, but you might not know it based on the ads being run by Republicans in competitive congressional primaries. Why it matters: Even as his approval rating droops amid rising gas prices and a sluggish economy , the president is still one of the most potent forces in Republican politics. - His endorsement is highly coveted by Republican congressional candidates, and the threat of his ire and anti-endorsement are often fear-inducing enough to keep would-be GOP defectors in line. Driving the news: Rep. Thomas Massie (R-Ky.), one of Trump's top primary targets this year, is blanketing the airwaves with ads saying he agrees with Trump "nearly all of the time." - "It's why in the past I've…