WASHINGTON (Reuters) - Flush with cash, political groups outside the White House are aggressively coming to President Donald Trump’s aid as he battles low public approval numbers, questions about his election campaign’s ties to Russia and a stalled legislative agenda. Through television attack ads and online campaigns normally seen only during the tumult of an election, the groups are helping Trump to strike back against his perceived enemies and boost his agenda, adding to the firepower of his Twitter account and the bully pulpit of the White House. On Tuesday, one of the groups, America First Policies, launched an attack ad against a senator from Trump’s own Republican Party who had balked at a Senate plan to overhaul healthcare that would leave millions more Americans uninsured. The attack angered Senate leader Mitch McConnell, who is struggling to rustle up the votes for the plan. It is the first time that a U.S. president has had Super PACs - political action committees that can raise unlimited amounts of money and typically operate during elections - or political non-profits, which do not have to disclose their donors or where they spend their money, actively working to support him after the dust of campaigning has cleared.  The pro-Trump groups are prohibited from coordinating with the White House, which declined to comment for this story. The New York Times reported that McConnell had complained to White House chief of staff Reince Priebus about America First Policies’ ad. The group later pulled the ad. America First Policies and the other pro-Trump groups were set up to promote Trump and his legislative agenda - healthcare reform, building a wall along the Mexican border, and pushing for lower taxation and deregulation. They are not allied to the Republican Party, which can pose a problem for Republican leaders as Tuesday’s attack ad showed. With Trump’s approval ratings sagging and his agenda now overshadowed by a federal investigation into his 2016 campaign’s ties to Russia, the groups are pouring resources into protecting Trump’s image, demonizing his opponents and amplifying his message that he is the victim of a witch-hunt. “The establishment is shaken, angry, losing control,” begins another new ad by America First Policies, which says on its website that it is a non-profit organization “supporting key policy initiatives.” Images of the U.S. Capitol, Democratic Senate Minority Leader Chuck Schumer and liberal MSNBC host Rachel Maddow flash in the background.  “Desperately waging an all-out war to protect their interest,” the narrator continues. “They lie, they leak, they leech onto power.” America First Policies is comprised of more traditionally conservative Republicans and was founded after the election by a close ally of Vice President Mike Pence, Nick Ayers.  The group said in a statement their mission was to promote Trump’s agenda and that they were not afraid to push House Republicans through grassroots and advertising to support the healthcare overhaul. The groups’ shift from policy promotion to attack mode, does not surprise Marjorie Hershey, a political science professor at Indiana University. “A lot of research tells us that negative ads tend to be more attention-getting than positive ads, and because Super PACs themselves aren’t on the ballot, they can afford to risk the unsavory reputation that negative advertisers often get,” Hershey said.  Strategists and political scientists say it is hard to know if the groups are actually moving public opinion. But the groups point to their fundraising as evidence of their success – much of it raised not from millionaires, but in small donations from voters. “Great America Alliance” - which was set up as a sister organization to a Super PAC created by Trump supporters Rudy Giuliani and Newt Gingrich - has spent $400,000 on an ad attacking former FBI Director James Comey, the group’s director, Eric Beach, told Reuters.     The video tried to discredit Comey, who was fired by Trump over his handling of the Russia probe, the week he testified before the Senate Intelligence Committee. “Just another DC insider in it for himself,” the ad concludes. The group launched a new ad this week featuring conservative media star Tomi Lahren attacking Robert Mueller, the special counsel now leading the Russia investigation. Mueller is investigating whether Trump may have attempted to obstruct justice by pressuring Comey to drop his inquiry.  On its website the group says its mission is “to advocate for a stronger economy, a more secure nation, and a society with less government intrusion and more freedom for American citizens.” Asked to reconcile its stated mission with the attack ads, the group’s director, Eric Beach, said, “Our goal is to really get on the ground and fight back. Our supporters want to get out there and fight ... the mischaracterization of not just Donald Trump’s rhetoric but also his policies.”  Alison Dagnes, a political science professor at Shippensburg University who specializes in Super PACS, said the well-resourced groups play a key role in spreading Trump’s message that what his supporters are reading or seeing in the media is false.  “They’re saying we see what’s happening now and you shouldn’t believe it.” The Committee to Defend the President, another Super PAC, launched an ad calling on supporters to “defend” Trump. The group’s leader, Ted Harvey, said unfair attacks on Trump had forced his group to shift their focus to defending the president instead of promoting his policies.  “Certainly, I would rather be talking about policies than talking about made-up lies that the Democrats and the mainstream media cabal have put together to discredit the administration from moving forward on its agenda,” said Harvey. (For a graphic on Super PAC spending for Trump versus Obama click tmsnrt.rs/2seIbj1)  