WASHINGTON (Reuters) - President Donald Trump, who has been criticized for not doing enough to help pass health care legislation, will do more traveling to try to drum up support for tax legislation, a senior White House aide said on Monday.  Specifically, Trump could travel to some Midwest states like Michigan and Wisconsin that he won during the 2016 presidential campaign but are still represented by Democrats in Congress. “In terms of travel, I think you will see him out there more ... in the states where we need votes,” said Marc Short, the White House’s legislative liaison.  The Republican effort to repeal Obamacare failed in the Senate last week, leaving party leaders looking ahead to try to tackle an overhaul of the tax code. But it has also left many questioning how taxes will be different, especially if Trump, who suffers from low national approval ratings, does not become more actively involved in pushing for the bill. Short said that unlike the health care, which he called more complicated, the White House has been working to build support for tax reform among national groups aligned with their ideology. His remarks came at a tax panel discussion sponsored by Americans for Prosperity, a group funded by Republican donors Charles and David Koch that organizes supporters across the country to contact their members of Congress in favor of conservative legislation.  Treasury Secretary Steve Mnuchin, speaking on the same panel, echoed his remarks.  “The message is [tax reform] may not be perfect for everything you want, but it’s going to be really really good for the economy and better than what we have,” Mnuchin said. 