President Trump's endorsement of suspending federal gas taxes pushes the idea higher on the political radar, but it still faces long odds. Why it matters: Some Republicans rushed to introduce bills, and a few Democrats have already endorsed the idea — but there are still serious obstacles that could keep Trump's comments from becoming reality. The federal tax is 18.3 cents for gasoline and 24.3 cents for diesel (with another .1 cent fee for addressing leaking underground tanks). A few dynamics