In a district Donald Trump won by 21 points in 2016, a Democratic newcomer is trying to pull off an upset victory for an open U.S. House seat in Arizona that has been held by Republicans since the early 1980s. Hiral Tipirneni, an emergency room physician and a cancer research advocate, is hoping to replicate Democratic wins in Pennsylvania, Alabama and other states in a year where opposition to the president's policies have boosted the party's chances in Republican strongholds. Still, many observers in Arizona see Tipirneni's odds against the Republican, former state Sen. Debbie Lesko, as slim. They face off in Tuesday's special election to replace former Rep. Trent Franks in Arizona's 8th District, who resigned in December amid sexual harassment allegations. Lesko represented parts of the district since 2009, and has an extremely strong base of support in a district Franks had locked up since 2003. She is opposed to Tipirneni's push to expand government-run health care, backs the president's tax cuts and is pushing his border wall proposal. 'I support securing the border, and part of that is paying for and putting up a border wall where it makes sense,' Lesko said. 'She is totally opposed and is on record of opposing any money going toward the border wall. This is not what our constituents want.' Tipirneni is pushing a plan that would allow people under retirement age to opt-in to Medicare coverage to provide new competition in health care markets, and opposes building a wall with Mexico while boosting enforcement through technology and drones and adding Border Patrol agents. She also said the fastest growing segment of immigrants in the U.S. illegally overstayed visas. 'To me a wall is not an answer, and quite frankly a lot of people have chimed in on a bi-partisan basis that a wall is not the answer,' she said. Tipirneni is seen as a fresh Democratic face with relatively moderate views that could get support during what could be developing as a wave year for the party. She says she's got a chance in a district that has seen a dearth of Democratic candidates for years as Franks was consistently re-elected with large majorities. 'I think there are a lot of recent elections to suggest that conventional wisdom doesn't necessarily apply,' Tipirneni said. 'There's a lot of enthusiasm in our base. We have a large chunk of independent voters that I think are very persuadable, and frankly there are Republicans who are feeling very disaffected.' National Republican groups are spending big to back Lesko, pouring cash into the suburban Phoenix district for television and mail ads and phone calls to voters to ensure her victory. House Majority Leader Kevin McCarthy flew in for a fundraiser last week. Lesko also said she welcomes the spending from national GOP organizations. 'Not only do I want to win, but I want to win by a lot so the Democrats can see that they don't have a chance in a red district,' she said in a recent interview. National Democratic groups haven't committed money to ads in the race, but in recent weeks, some progressive groups have been spending to back Tipirneni, and she has been running non-stop TV ads in the last week of the election. Still, the lack of Democratic Party spending is a sign they don't see the race as competitive, said Constantin Querard, a Republican political consultant. The numbers are strongly in Lesko's favor — in the Feb. 27 primary, 2 out of 3 ballots were cast for a Republican. The district sprawling across western Phoenix suburbs includes some of the most conservative areas of the red state, including the retirement communities of Sun City and the Glendale home of former GOP Gov. Jan Brewer, who never lost an election and campaigned for Lesko in a 12-way GOP primary. Early ballot returns in the special election strongly favor Republicans, who enjoy a 41 percent to 24 percent voter registration advantage in the district, with another 34 percent not choosing a party affiliation. Of more than 150,000 early ballots returned as of Friday, nearly 74,000 came from registered Republicans and only about 40,000 from Democrats. Independents in the district tend to skew Republican and have returned about 34,000 completed ballots, according to data compiled by the Arizona Secretary of State's office.