Recently, several really terrible ideas for blocking Roy Moore from becoming a senator were floated by right-wing pundits, most notably Hugh Hewitt.
The first was canceling the special election entirely via an act of the Alabama legislature. The second was having Sen. Strange resign early and use that to "reset" the process of a special election, with the governor calling a new one. The third was the Senate refusing to seat Moore, necessitating a new election.
None of these actually works.
The first doesn't work because the election is already underway: we've already held a primary, the candidates are already making major expenditures, and any major legal change to the process at this point to preclude one party's loss would be unlikely to survive a federal court challenge. (It would also require Gov. Kay Ivey to engage in the same sort of political chicanery that her predecessor, the extremely disgraced Robert Bentley, did with this seat when he appointed Strange in the first place, which is a big part of why the Alabama GOP is in this mess to begin with. Ivey is extremely popular now, and for both self-interested reasons and good government ones would likely have zero desire to try a scheme like this).
The second doesn't work because Strange's resignation wouldn't actually create a new vacancy: the vacancy that needs to be filled already exists--it was created by Sessions' resignation, and isn't really affected by what Strange does. Strange is a placeholder, appointed by Bentley to fill "the vacancy therein caused by the resignation of United States Senator Jeff Sessions" (as it says in the certificate of appointment that Alabama sent to the Senate when Strange was named to the seat). That vacancy exists irrespective of what Strange does: all he can do by quitting is leave the state less represented in the Senate.
The third doesn't work because there's actually an on-point Supreme Court decision from 1969, Powell v. McCormack, that says the best the Senate could do would be to seat him, and then vote to expel him (which takes 2/3rds of members). That would create a new vacancy, which could be filled in the 2018 election, and allow Ivey to appoint a replacement, but man, getting <strike>66</strike> 67 Senators to vote to overturn the will of the voters is a big lift.
All things considered, the best thing for Alabama, for the Senate, and for the country is to do the most obvious thing to keep Moore from becoming a Senator: help Doug Jones kick his ass.