A profile in courage. Photo: Andrew Harrer/Bloomberg via Getty Images

Arizona Senator Jeff Flake, who hasn’t stood up to President Trump in any meaningful way but nevertheless wrote a book about doing so, has drawn a top Democratic challenger in his race for reelection in 2018.

Phoenix’s NBC affiliate reports that Democratic congresswoman Kyrsten Sinema, currently serving her third term in the House, plans to run against Flake next year. Sinema hasn’t announced her candidacy officially, but released a statement that sounded close to a confirmation: “I’ve heard from many Arizonans encouraging me to run for the United States Senate. It is something I am seriously considering. When I make any decisions, Arizonans will be the first to know.”

Sinema is the first-ever openly bisexual member of Congress, representing a blue-leaning district in suburban Phoenix that she has won with increasing ease since her first run, in 2012. She has moved to the political center in recent years, joining up with the Blue Dog coalition, often a scourge of liberals. Her moderate stances may play well in Arizona, an incipient swing state that still leans Republican.

Flake never endorsed Trump during the GOP presidential primaries, and often denounced the president for his callousness during the campaign. In his new book, Conscience of a Conservative (the title echoes Barry Goldwater’s 1960 volume), Flake flays his own party for abandoning bedrock principles like free trade and small government in favor of the feverish know-nothingism that gave rise to Trump.

But, as many have noticed, Flake’s noble rhetoric doesn’t exactly align with his actions, which have included confirming Trump nominees whose philosophies seem directly opposed to his. For example, he green-lighted an anti-NAFTA nominee to be the United States trade representative, and voted to confirm a judge who had endorsed the Obama birther conspiracy, which Flake has railed against. In a less surprising move, Flake approved the “skinny repeal” health-care bill that came within one vote of Senate passage.

Yet despite his acquiescence to almost all of the Trump agenda, Flake has drawn plenty of flak from his right. The thin-skinned president has expressed interest in unseating him; the White House has met with at least three potential primary opponents, and a major Trump donor is investing in the effort to oust Flake. Kelli Ward, a loopy right-winger who recently urged John McCain to resign so she could fill his seat, has already announced a campaign. Last week, she assailed Flake in the pages of USA Today for aligning himself with the “radical left.”

Between his public disdain for Trump and his unwillingness to take a real stand against the president, Flake boasts some of the lowest approval ratings of any senator, and is seen as one of 2018’s most endangered incumbents.

Have fun next year, Jeff!