First Read is your briefing from Meet the Press and the NBC Political Unit on the day's most important political stories and why they matter.

WASHINGTON — The 2018 fight for the Senate got more interesting this week — and it could be even more interesting after next week’s special Senate race in Alabama.

First, we learned that former Tennessee Gov. Phil Bredesen, a Democrat, was jumping into the contest to fill the Senate seat being vacated by retiring Sen. Bob Corker, R-Tenn. The Cook Political Report immediately put Tennessee in the Toss Up category, while Nathan Gonzales’ Inside Election is keeping it Solid Republican. Still, if there’s a wave in 2018, Bredesen’s bid helps to give Democrats a third pick-up opportunity when they currently need three to take back control of the Senate next year.

Second, Sen. Al Franken’s, D-Minn., decision to resign his seat in the coming weeks after accusations of sexual harassment sets up ANOTHER Senate election to watch in 2018. While Hillary Clinton won Minnesota by just 1.5 points in 2016, the current political environment (with President Trump’s job-approval rating in the 30s) will make it tough for Republicans to carry this Dem-leaning state in 2018.

And third, next week’s special election in Alabama could further scramble the 2018 Senate map. Currently, Republicans hold a 52-48 majority in the Senate, which means that Democrats need to net a gain of three pickups. But if Democrat Doug Jones wins in Alabama next week, the GOP’s majority gets reduced to 51-49 and the Dem magic pick-up number becomes two.

The 2018 cycle started out with a terrible map for Democrats, with them having to defend 25 Senate seats, including a whopping 10 in states that President Trump won in 2016. But on Tuesday, we’ll find out if their path to a majority becomes much more realistic.

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If Jones wins, pickups in Arizona and Nevada — plus Democrats successfully defending all of their seats — would give them control of the Senate. That’s far from easy. But it looks more doable than it did a year ago.

Another member of Congress to resign after allegations of potential sexual misconduct

Hours after Franken announced his decision to step down, another member of Congress — Rep. Trent Franks, R-Ariz. — said he was resigning after the House Ethics Committee said it was opening an investigation into potential sexual misconduct.

NBC’s Leigh Ann Caldwell and Alex Moe: “Franks said in a statement that he had discussed his interest in finding a surrogate mother with two women in his office, making them uncomfortable. His wife has struggled with infertility, he said. The Ethics Committee said that it was convening a subcommittee to determine if Franks ‘engaged in conduct that constitutes sexual harassment and/or retaliation for opposing sexual harassment.’ The statement, which cited the ethics investigation, said his resignation is effective on Jan. 31.”

Meanwhile, the House Ethics Committee says it will be taking a new look into the allegations against Rep. Blake Farenthold, R-Texas. The Texas Tribune: “Members of the U.S. House Ethics Committee unanimously voted Thursday to establish a subcommittee to investigate allegations that U.S. Rep. Blake Farenthold, a Corpus Christi Republican, sexually harassed a subordinate several years ago. The matter appeared to be resolved two years ago. But it resurfaced as a heightened awareness of sexual harassment has swept workplaces across the country, including U.S. congressional offices.”

Trump White House criticizes African-American lawmakers who are skipping his appearance at civil rights museum

"U.S. Reps. John Lewis and Bennie Thompson will stay away from Saturday’s opening of the Mississippi Civil Rights Museum, citing the attendance of President Donald Trump," USA Today reports. "Lewis and Thompson, both Democratic leaders, had planned to attend Saturday."

White House Press Secretary Sarah Huckabee Sanders issued this response: “We think it’s unfortunate that these members of Congress wouldn’t join the president in honoring the incredible sacrifice civil rights leaders made to right the injustices in our history. The president hopes others will join him in recognizing that the movement was about removing barriers and unifying Americans of all backgrounds.”

But the Congressional Black Caucus fired back that Lewis is one of the civil rights leaders being honored. “It’s laughable that the White House is criticizing John Lewis and Bennie Thompson for not attending the opening of a civil rights museum that honors the sacrifice of ....wait..... John Lewis, Bennie Thompson, and many others,” said Rep. Cedric Richmond, D-La., chair of the Congressional Black Caucus. “This White House is not serious about civil rights. From dismantling the civil rights division in DOJ to equating peaceful people who protested racism to Neo-nazi’s and White Supremacists, they just don’t get it.”

Trump holds rally in Pensacola, Fla.

Before his appearance in Mississippi tomorrow, President Trump tonight heads to Pensacola, Fla. – which is on the border between Florida and Alabama – for a campaign rally at 8:00 pm ET.

Here's how the AP has described Trump's visit: “President Donald Trump will appear at a campaign-style rally in Pensacola, Florida … a move that brings the president less than 20 miles from the Alabama border just four days before a special election that will decide the fate of embattled Republican Senate candidate Roy Moore.”

Drain the swamp? Interior Secretary Zinke booked government helicopters to attend DC events

Politico: Interior Secretary Ryan Zinke spent more than $14,000 on government helicopters this summer to take himself and staff to and from official events near Washington, D.C., in order to accommodate his attendance at a swearing-in ceremony for his replacement in Congress and a horseback ride with Vice President Mike Pence, according to previously undisclosed official travel documents. The travel logs, released to POLITICO via a Freedom of Information Act request, show Zinke using taxpayer-funded vehicles from the U.S. Park Police to help accommodate his political events schedule.”

Zinke has been on the job less than a year, but “Zinke” and “controversy” already has some robust search results.