INDIANAPOLIS, Ind. (Reuters) - U.S. Republican Ted Cruz carefully left the door open to a future run for president on Tuesday after a campaign that outlasted a long list of rivals but could not overcome the anti-establishment appeal of Donald Trump. Cruz, who still holds his U.S. Senate seat from Texas for another two years before facing re-election in 2018, told supporters in Indiana where he lost badly in the state’s primary, that his campaign was suspended but that his role in the future of the party was not over. “I am not suspending our fight for liberty,” Cruz said. He could be among several Republicans who may resurface in the 2020 presidential campaign after failed bids this time, should the presumptive nominee this year, Donald Trump, falter in the Nov. 8 election. The 45-year-old Cruz became a favorite of evangelicals and the party’s conservative wing after he won Iowa’s caucuses, the first nominating contest of the race. He built the best organization of any other Republican campaign this year, but his zealous conservatism fell victim to Trump’s outsider appeal. In the days leading up to the Indiana vote, Republicans were reminded of Cruz’s take-no-prisoners approach in the Senate when former House of Representatives Speaker John Boehner called him “Lucifer in the flesh” and the “most miserable son of a bitch” he had ever worked with on Capitol Hill. The next test for Cruz will be determining what role he will play in the general election and whether, after months of attacks, he will throw his support behind Trump. Trump clearly would like his support as he tries to unite the Republican Party after a bitter primary battle. “I want to congratulate Ted Cruz,” Trump said in New York at a victory rally. “He’s a tough, smart competitor.” Cruz, the son of a Cuban immigrant, gained prominence in conservative circles as the Texas solicitor general, arguing cases on religious liberty and states’ rights. After he was elected to the Senate in 2012, he alienated colleagues but drew national attention for his role in the 2013 government shutdown.  In a 21-hour talkathon, in which he sought to convince lawmakers to cut funding for President Barack Obama’s signature health-care law, Cruz chided the “cheap suits” and “bad haircuts” of some politicians and read the children’s book “Green Eggs and Ham” by Dr. Seuss. Cruz cast himself as the leader of a grassroots conservative army when he jumped into the White House race in March 2015, and he argued he was the only candidate who could unite disparate groups of the Republican Party, such as social conservatives and libertarians. He was buoyed by early wins in Iowa and at home in Texas, and Cruz claimed he was the Republican best suited to take on Trump after candidates favored by the party’s establishment, such as Jeb Bush, left the race. As Cruz ended his campaign, vendors hawking campaign-themed apparel outside the Indianapolis event quickly discounted the merchandise bearing Cruz’s campaign slogan, lowering prices from $20 a shirt to just $5. Supporters lingered in the remodeled train station where Cruz held his rally, some crying and others hugging one another as the news sunk in. Despite having long odds when he announced his candidacy, Cruz beat expectations.      “Cruz certainly performed better than anyone in Washington expected, and he still has Texas wired. However, no one is stopping the Trump machine now,” Texas-based Republican strategist Joe Brettell said. 