The Alabama Senate race is tightening. Republican Roy Moore was tied with Democrat Doug Jones in a Fox News poll released this week.

A previous poll showed Moore leading by 8 points while a survey before that had him ahead of Jones by just 5. Moore's lead in the RealClearPolitics polling average is just 4.4. points in the December special election to fill the remainder of the Senate term Jeff Sessions, now the attorney general of the United States, was elected to in 2014.

For context, Sessions had no Democratic challenger that year and was re-elected with over 97 percent of the vote. No Democrat has held one of Alabama's two Senate seats since Howell Heflin retired in 1997 and was replaced by Sessions.

No Democrat has won a Senate race in the state since Richard Shelby was last re-elected as one in 1992; he switched to the Republican Party in 1994.

A Democratic strategist consulting for Jones told the Washington Examiner that even Republican donors in Alabama were expressing a willingness to open up their wallets to oppose Moore, a former state judge with a history of controversial statements and actions.

Moore's own fundraising appeals noted the Fox News poll in an effort to get conservative donors to become similarly generous with their campaign in an effort to counter the "avalanche of lies" Democrats have unleashed.

"It's only been a matter of days since the DNC launched their all-out war to destroy me on December 12 and keep me out of Washington," Moore said in one fundraising letter. "But it's already having an impact."

Even if Republicans have a bad year in 2018 overall, it would be difficult for Democrats to retake the Senate. They are defending many more seats than the GOP and have ten incumbents running in states President Trump won last year. This includes states like West Virginia, North Dakota, and Montana, where polling shows Trump remains popular.

But a lucky break in a state like Alabama is what Democrats will need to put the Senate in play. They are already competing to eliminate the Republicans' 24-seat House majority, starting with the 23 GOP-held districts that voted for Hillary Clinton last year.

This raises questions about former White House chief strategist Steve Bannon's project of recruiting pro-Trump candidates for Republican Senate primaries, possibly challenging nearly every GOP incumbent up for re-election next year except for Sen. Ted Cruz, R-Texas.

Moore was a candidate Bannon backed in the Republican primary runoff over appointed Sen. Luther Strange, R-Ala. Strange had the support of Trump and Senate Majority Leader Mitch McConnell, R-Ky. Moore nevertheless prevailed easily, carrying 63 of Alabama's 67 counties and winning by nearly 10 points statewide.

Local conditions, such as the unproven perception that Strange benefited from a corrupt bargain with disgraced former Alabama Gov. Robert Bentley, doomed the incumbent. But this didn't stop Bannon and his allies from taking a victory lap after the primary.

Conservative primary challenges to Republican incumbents or leadership-backed candidates have been controversial for decades. When Cruz launched his campaign in Texas, many on the Right felt such a reliably red state should be represented by a lawmaker much more conservative than retiring Sen. Kay Bailey Hutchison. Similar logic propelled Sens. Rand Paul, R-Ky., Marco Rubio, R-Fla., and Mike Lee, R-Utah, to comfortable general election wins after defeating establishment-backed GOP candidates.

It took two tries for Sen. Pat Toomey, R-Pa., to beat centrist Sen. Arlen Specter. Toomey's second Republican primary campaign drove Specter, a five-term incumbent, out of the party entirely. Rubio had the same effect on former Florida Gov. Charlie Crist, now a Democratic congressman.

Not all of these campaigns have gone equally well, however, and Bannon might need to rely on particularly quirky candidates to take up the populist mantle. Many candidates who have tried to imitate Trump have not proven as politically skillful.

McConnell was explicit about the past failure of some Republican insurgents to translate well in the general election during his joint press conference with Trump at the White House on Monday.

"Back in 2010 and 2012, we nominated several candidates — Christine O'Donnell, Sharron Angle, Todd Akin, Richard Mourdock," McConnell said. "They're not in the Senate. And the reason for that was that they were not able to appeal to a broader electorate in the general election."

In 2018, Republicans will be trying to win or hold Senate seats in three of the four states where these candidates were defeated in past election cycles.

Some Republicans fear Moore will be like Akin: a social issues warrior with a history of pronouncements on religion and homosexuality that other GOP candidates will be pressured to comment on or condemn. He already stands a chance of being like Akin in blowing what should be a winnable Senate race.

Despite Moore's lackluster poll numbers, he remains the favorite. Democrats are reluctant to commit significant resources to Alabama, even if a close finish would bolster already solid candidate recruitment for next year, and fear nationalizing the race will backfire. Democrats have complained about their party's efforts to mobilize black voters this year, causing former President Obama to hit the campaign trail, and low African-American turnout would make it nearly impossible to beat a Republican in Alabama.

Even a Moore win could be used against Republicans in less-conservative areas, as well as to bolster liberal fundraising.