Former Pennsylvania senator Rick Santorum’s twin wins in Alabama and Mississippi Tuesday night are almost certain to give him what he has long wanted: A one-on-one race with former Massachusetts governor Mitt Romney.

The victories by Santorum came in the political backyard of Newt Gingrich and are likely to symbolically — if not literally — end the former speaker’s hopes in the race.

“The time is now for conservatives to pull together,” Santorum urged in his victory speech Tuesday night from Lafayette, La.

Republican presidential candidate, former Pennsylvania Sen. Rick Santorum greets supporters at the Original Dreamland BBQ in Tuscaloosa, Ala. Monday, March 12, 2012. (AP Photo/The Tuscaloosa News, Dusty Compton)

Gingrich has pledged to remain in the presidential race all the way to the Republican National Convention in Tampa, Fla., and he still may choose to do that. “He is not going to drop out,” his daughter Jackie Cushman said on MSNBC on Tuesday night. “He is not interested in that.”

But Santorum’s wins on Tuesday are likely to trigger a rallying effect among conservatives, a movement that Gingrich was (barely) able to hold off on Super Tuesday when he won his home state of Georgia. (Aside from his home state, Gingrich has won only one other state — South Carolina — way back on Jan. 21.)

And, no matter what Gingrich does, the numbers from the exit polls in Alabama and Mississippi are a striking sign that Santorum is rapidly emerging as the preferred conservative choice.

Among those who said a candidate’s conservative credentials were the most important attribute in making their choice, 51 percent of Alabamians went for Santorum while just 34 percent voted for Gingrich. In Mississippi, it was 53 percent for Santorum to 34 percent for Gingrich. Roughly one in four Alabama voters said a “strong moral character” was the most important candidate attribute; Santorum took 61 percent to just 7 percent for Gingrich among that bloc.

For all intents and purposes then, the Republican race has narrowed to a two-man race with Illinois, which votes on March 20, looming as the next huge test for both Santorum and Romney.

Polling released over the weekend in Illinois shows Romney with the narrowest of leads over Santorum although it’s unclear whether the positive press coverage the former Pennsylvania senator will receive coming out of Tuesday night’s votes will alter the electoral calculus in the Prairie State.

Romney’s losses in both Alabama and Mississippi will further complicate his campaign’s efforts to focus the race solely on the delegate count, which continues to heavily favor him.

Not that they aren’t trying, of course. “Our goal was to take one-third of the delegates and possibly do slightly better than that,” Romney spokesman Eric Fehnrstrom said on CNN Tuesday night. “I think we will exceed that goal.”

Romney’s inability to win a single Southern state where he has shared the ballot with Santorum and Gingrich coupled with his ongoing struggles with very conservative voters and those who identify themselves as evangelical Christians are sure to provide considerable fodder to Romney’s critics.

It’s impossible for Romney to make the case that his nomination is inevitable when he keeps putting “L’s” on the board. It’s equally difficult for Santorum to argue he can overcome Romney’s delegate edge unless he can win a big, delegate-rich state where Romney is favored.

Still, Illinois will almost certainly be the first state where Santorum gets what he always wanted: a clear shot at Romney. Now he just has to prove he can hit the target.