Republican U.S. Sen. Jeff Flake is getting challenged from both the right and the left in his bid for a second term. The first hurdle will be a competitive primary. If he clears that obstacle, he will likely face a competitive challenge from Democratic U.S. Rep. Kyrsten Sinema, who announced her candidacy via YouTube video last night.

Late last year, Kelli Ward, a former state Senator, announced that she would challenge Flake in the GOP primary. Ward ran against U.S. Sen. John McCain in the 2016 primary, taking 40 percent of the vote. That percentage says more about the very conservative nature of the state’s Republican primary electorate and its dislike of McCain than it does about Ward or the campaign she ran. While Ward didn’t get much support from national conservative groups in 2016, she has gotten their attention in this race, which has improved her fundraising. President Trump is no fan of Flake because the incumbent has been critical of him and some of his proposals. In response, Trump has gone after Flake on Twitter and has name-checked Ward on several occasions; it’s something short of an endorsement, but has boosted her standing nonetheless. It hasn’t helped that Flake recently authored a book – Conscience of a Conservative: A Rejection of Destructive Politics and a Return to Principle – that has not been well received by some conservatives (although few voters primary voters are likely to have read it). State Treasurer Jeff DeWit, an avid Trump supporter, and former state party chairman Robert Graham have also been mentioned as possible primary challengers. It would actually help Flake if one or both decided to run since they would split the anti-Flake vote with Ward.

Sinema, 41, was first elected in 2012 to represent the 9th congressional district, which encompasses east Phoenix, Tempe and parts of Scottsdale. Her first race for what was then a newly created seat was a nail-biter that she won with 49 percent; she was re-elected in 2014 and 2016 with 55 percent and 61 percent of the vote, respectively. Sinema is a more centrist Democrat and a member of the House’s Blue Dog Coalition, which may earn her a challenge to her left in a primary. Phoenix Mayor Greg Stanton has been mentioned as a potential candidate, but has also said he might run for Sinema’s House seat. To date, retired administrative law judge Richard Sherzan and attorney Deerdra Abboud have announced their candidacies, but neither pose a threat to Sinema. Senate Majority PAC, Minority Leader Chuck Schumer’s leadership PAC, released a poll conducted by Gerstein Bocian Agne Strategies (August 30-September 7 of 600 likely voters and an additional 500 likely GOP primary voters) that showed the depths of Flake’s vulnerability. Among primary voters, Flake’s job ratings were 34-approve to 59-percent disapprove. In a primary trial heat, Ward was ahead by a wide 58-percent to 31-percent margin. Among general election voters, Sinema was ahead of Flake, by seven points, 47 percent to 40 percent.

Flake’s challenge seems to be getting much more difficult now that there is a first-tier Democratic candidate in the race. The contest moves to the Toss Up column.