PHOENIX - Nearly three months after Sen. Jeff Flake announced he would not seek re-election in 2018, former Maricopa County Sheriff Joe Arpaio announced he will run for the seat.

Arpaio, said on Twitter, he was seeking a Senate seat for "one unwavering reason: to support the agenda and policies of President Donald Trump in his mission to Make America Great Again." His profile photo has changed to a campaign sign.

Names from both sides of the aisle have been thrown into the mix since Flake took to the Senate floor in October. The self-proclaimed "toughest sheriff" threw in his own on Tuesday, but what other names are in the hat?

PREVIOUS: Arizona Sen. Jeff Flake announces he will not seek re-election

Here are some of the biggest names in the race so far:

Kelli Ward

Former State Senator Kelli Ward lost the 2016 GOP primary to Sen. John McCain, but didn't waste any time before announcing she would challenge Flake.

Steve Bannon publicly endorsed Ward at a Scottsdale rally in October just days before Flake announced he is not running.

She welcomed Arpaio to the race.

Martha McSally

Rep. Martha McSally hasn't officially announced she is running but in November she told her Republican colleagues that she has plans to do so.

12 News' political reporter Brahm Resnik tweeted that McSally will officially announce her campaign this Friday.

Kyrsten Sinema

Phoenix Democratic Congresswoman Kyrsten Sinema announced she would also run back in September. Sinema was first elected in 2012 and, though Democrat, has been known to be more center-left in her policies.

Like Ward, Sinema released a statement about Arpaio's run. Her words took a different tone.

Deedra Abboud

Attorney and community activist Deedra Abboud made headlines when she received hateful attacks on her Facebook page for being Muslim back in July. Flake tweeted Abboud in support, saying to "hang in there" and that she will find wonderful people in Arizona.

READ: Jeff Flake tweets support to Muslim candidate under attack on Facebook

And this is just for Flake's seat. Currently, the future of both Senate seats are unclear. If Sen. John McCain, who is battling cancer, retires this year, a republican successor will be appointed by Gov. Doug Ducey, but there are a few different ways Ducey can do that.

HERE'S HOW: What happens if John McCain retires from the Senate?

The 2018 Senate race is one that could determine whether Republicans keep control of the Senate in 2018. If Flake's Senate speech and Arpaio's campaign announcement are precursors to how this election will play out, there are some interesting times ahead.

The primary will be Aug. 28 followed by Election Day on Nov. 6.