Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- By just after 8 a.m. ET Tuesday, President Trump had already tweeted his support for Sen. Luther Strange's candidacy in Alabama twice. "Big day in Alabama. Vote for Luther Strange, he will be great!," said Trump in one tweet. Strange, appointed by then Gov. Robert Bentley (R) to replace now-Attorney General Jeff Sessions, faces a serious fight today in the form of Roy Moore, a controversial ex-chief justice of the state's highest court, and Rep. Mo Brooks. (If no candidate gets 50% of the vote today, the top two advance to a runoff next month.) In search of the state of play in Alabama -- and what it means for Trump and Senate Majority Leader Mitch McConnell, who has also been working hard for Strange, I reached out to Brian Lyman of the Montgomery Advertiser for some perspective. Our conversation, conducted via email and only lightly edited for flow, is below

Cillizza: Why hasn't Sen. Luther Strange wrapped this up? He's an incumbent (sort of) with the support of Donald Trump and Mitch McConnell?

Lyman: There's a few reasons for this, mostly Alabama-based. Strange has strained relationships with key members of the Alabama Republican establishment. He was kind of stand-offish toward the Alabama Legislature when he was attorney general, and that contributed to clashes. At one point, the Legislature zeroed out the attorney general office's funding in a dispute over national mortgage settlement funds. The prosecution of former Alabama House Speaker Mike Hubbard, which Strange recused himself from, didn't help, and further hurt some key relationships Strange has with what should be his natural constituency, the business community.

The key reason, though, is former Gov. Robert Bentley. Strange interviewed for the US Senate job and accepted the appointment while the Alabama attorney general's office was investigating Bentley. Strange refused to say whether or not there was an investigation leading up to the appointment; it was only confirmed after Steve Marshall, his successor, recused himself. Bentley -- whose popularity was sinking with Republicans when Strange took the appointment -- later pleaded guilty to two campaign finance violations and resigned. Strange really hasn't addressed the circumstances of his elevation. Whether he could do that without inflicting major political damage is an open question. He might have to wrestle with it should he make a runoff, because the issue remains on voters' minds (see, for instance, this AP story where one says Strange has "Bentley cooties.")

Finally, there's Roy Moore. Once the former chief justice entered the race, every other campaign could write off at least 25 to 30% percent of the electorate. Moore has a base that sticks with him and comes out to vote. In fact, this kind of contest -- a primary for a special election in an off-year -- plays to the judge's strengths.

Cillizza: Is this a two-way race between Strange and Roy Moore? Or does Rep. Mo Brooks have a real chance?

Lyman: The honest answer is I don't know. The reason I don't know is turnout. Only 20 to 25% of the electorate is expected to come out for the primary. At that level of participation, I wouldn't be surprised by any result -- from nothing happening as we expect to everything happening as we think it might.

If Brooks can run up his numbers in north Alabama; do well in the Wiregrass and attract voters from State Sen. Trip Pittman in coastal Baldwin County (a Republican bastion) he might have a chance. The attack ads from Sen. Mitch McConnell's political action committee, though, have hurt him statewide, and his path is harder than the one Strange or Moore are on.

But if you have just 25% of the electorate coming out, brace for unpredictability.

Cillizza: Is this race simply a contest of which candidate can be the most Trump-like? If so, who is doing it best? If not, why not?

Lyman: I wouldn't call any of the major candidates Trump-like.

Strange is reserved; Moore has a tendency to speak in legalisms and Brooks, who has a history of inflammatory remarks, follows (for better or worse) a rigid Tea Party philosophy that Trump, on the campaign trail at least, broke from.

There are no "Never Trumpers" in the race. But Strange has been semi-successful making the Republican primary a referendum on who is most loyal to Trump. Brooks, who could have spent money on ads attacking Strange for his Bentley connections, used most of his air time to rebut accusations that his devotion to the president was not all-consuming.

The failure of ACA repeal gave Moore and Brooks an opening. Ignoring Trump's missteps on the bill, they focused all the blame for the end of that Republican goal on McConnell. They're clearly hoping that the Senate Majority Leader's unpopularity and the failure of ACA will matter more to Republican voters than who loves Trump best.

Cillizza: If Roy Moore, a hugely controversial figure in Alabama and nationally, wins today what lessons can we or should we draw about the state of the GOP in Alabama?

Lyman: I thought about this one a lot. In a low turnout election, I'm not quite sure any big lessons can be drawn. An outright Moore win -- without a runoff -- could be ascribed to his base, who will come out for him in any situation, good or bad. If Moore got that far, turnout would likely be on the low end of projections. You could also say that the appeal to Trump only motivates voters so much.

It will be interesting to see what the business wing of the Alabama Republican Party -- which isn't particularly fond of Moore -- would do if Moore became the nominee, whether today or after a Sept. 26 runoff. The business wing sat on their hands in the 2012 race for chief justice, and they would have to weigh whether having a Republican in the Senate is more important than their antipathy to him (in part for his social stands, but also for anti-arbitration opinions he's written).

On his own, Moore struggles to raise money and reach beyond his base. Democrat Bob Vance, who started late in that 2012 race, raised a ton of money, ran a strong campaign and came within a few points of beating Moore, running eight points ahead of Barack Obama in Alabama. If the business community is still meh toward Moore, the Democrats have an opportunity -- not a guarantee and maybe not even a 50/50 chance, but an opportunity -- to make a race. If THAT happened, the lesson would be that the GOP, the dominant force in Alabama politics for the past seven years, would be splitting like other dominant state-level parties around the country.

Cillizza: Finish this sentence: "In this race, Donald Trump is about as popular as ." Now, explain.

Lyman: "attacks on Mitch McConnell."

The candidates praise the president and (except for Strange) attack the Senate Majority Leader, or attack the Senate Majority Leader and praise the president. We'll have to see which approach is more popular with voters.