Sen­ate Ma­jor­ity Lead­er Mitch Mc­Con­nell offered mem­bers a snow-week­end sur­prise late Wed­nes­day night: Quietly tee­ing up a de­bate on the leg­al un­der­pin­ning for the fight against IS­IS.

After months of wor­ry­ing that such a res­ol­u­tion—known as an au­thor­iz­a­tion for the use of mil­it­ary force—would tie the next pres­id­ent’s hands, Mc­Con­nell’s move to fast-track the meas­ure sur­prised even his top deputy, Sen­ate Ma­jor­ity Whip John Cornyn, who was un­aware that Mc­Con­nell had set up the au­thor­iz­a­tion.

“He did?” Cornyn asked Na­tion­al Journ­al on Thursday morn­ing.

The AUMF put for­ward by Mc­Con­nell would not re­strict the pres­id­ent’s use of ground troops, nor have any lim­its re­lated to time or geo­graphy. Nor would it touch on the is­sue of what to do with the 2001 AUMF, which the Obama ad­min­is­tra­tion has used to at­tack IS­IS des­pite that au­thor­iz­a­tion’s in­struc­tions to use force against those who planned the 9/11 ter­ror­ist at­tacks. By con­trast, the leg­al au­thor­ity put for­ward by the ad­min­is­tra­tion last Feb­ru­ary wouldn’t au­thor­ize “en­dur­ing of­fens­ive ground com­bat op­er­a­tions” and would have ended three years after en­act­ment, un­less reau­thor­ized.

After sit­ting on the pres­id­ent’s pro­posed AUMF for nearly a year, amid deep in­fight­ing in the Sen­ate over the meas­ure, Mc­Con­nell’s move came as a sur­prise to many mem­bers. Just in Decem­ber, Mc­Con­nell dis­missed the idea of bring­ing up a new au­thor­iz­a­tion, telling re­port­ers: “It’s clear the pres­id­ent does not have a strategy in place, so it would be hard to fig­ure out how to au­thor­ize a non-strategy.”

Don Stew­art, Mc­Con­nell’s spokes­man, said Thursday in an email that the new AUMF “is not the one the [p]res­id­ent asked for” and “not one that would tie the [p]res­id­ent’s hands.”

After 18 months, I feel like the in­sti­tu­tion might be fi­nally wak­ing up that this is a threat. Sen. Tim Kaine, D-Va.

Stew­art ad­ded that the pro­cess Mc­Con­nell used to set up the AUMF, known as “Rule XIV,” merely sets up the au­thor­iz­a­tion for a fu­ture vote, but does not put it on the cal­en­dar—mean­ing a vote could come at any time, or not at all. The res­ol­u­tion already has four Re­pub­lic­an co­spon­sors: Sens. Lind­sey Gra­ham, Daniel Coats, Joni Ernst, and Or­rin Hatch.

That came as news to many mem­bers Thursday. Sev­er­al sen­at­ors said they were un­aware that Mc­Con­nell had moved to fast-track an au­thor­iz­a­tion and some Re­pub­lic­ans im­me­di­ately poin­ted out is­sues with the pro­pos­al. Sen. Jeff Flake, who in­tro­duced a more lim­ited AUMF with Vir­gin­ia Demo­crat Tim Kaine last June, said: “We need to pass one—we don’t need to just make a polit­ic­al state­ment.”

“I just know that it’ll be dif­fi­cult to get Demo­crat­ic sup­port on this,” he ad­ded.

Sen­ate For­eign Re­la­tions Chair­man Bob Cork­er said that there is still a “wide di­versity” of opin­ions on the is­sue. Some Demo­crats were crit­ic­al of even the pres­id­ent’s own draft AUMF, warn­ing that they’d need ad­di­tion­al re­stric­tions from the ad­min­is­tra­tion on troop levels and geo­graph­ic bound­ar­ies be­fore they could sup­port any au­thor­iz­a­tion. Re­pub­lic­ans, mean­while, wor­ried deeply about re­strict­ing the pres­id­ent as this ad­min­is­tra­tion, and the next one, work to com­bat IS­IS.

Cork­er’s com­mit­tee—and the Sen­ate at large—was so deeply di­vided over the pres­id­ent’s AUMF pro­pos­al in Feb­ru­ary that the pan­el ul­ti­mately dropped the is­sue, with Cork­er ar­guing with the ad­min­is­tra­tion that no new au­thor­iz­a­tion was needed. “I don’t think it changes any­thing,” he said, of the new res­ol­u­tion.

“I’m in the same place that I’ve been—and that is I be­lieve the ad­min­is­tra­tion has the au­thor­ity to do what they’re do­ing,” he ad­ded. “They be­lieve they have the au­thor­ity to do what they’re do­ing. If a con­sensus de­vel­ops and I be­lieve that something con­struct­ive re­l­at­ive to us deal­ing with IS­IS might come out of it then cer­tainly I’d be glad to con­sider it.”

Still, sev­er­al long-time ad­voc­ates for passing a new meas­ure au­thor­iz­ing the ad­min­is­tra­tion’s war against IS­IS were pleased to see an AUMF mov­ing, however slightly, for­ward.

I’m en­cour­aged by the fact that [McConnell]’s not run­ning away from this is­sue any longer. Sen­ate Minor­ity Whip Dick Durbin, D-Ill.

“This is the right thing,” said Gra­ham, a co­spon­sor on the new AUMF res­ol­u­tion. “This is the right in­fra­struc­ture to have.”

“If our Demo­crat­ic friends don’t want to give this pres­id­ent and oth­er pres­id­ents the abil­ity to go after IS­IS without lim­it­a­tion to geo­graphy, time and means—be on the re­cord,” he ad­ded.

Kaine, a Demo­crat who has ag­gress­ively ad­voc­ated for an AUMF, was thrilled Thursday that the Sen­ate could soon take up de­bate, though he ad­ded that he hasn’t yet seen the de­tails. “After 18 months, I feel like the in­sti­tu­tion might be fi­nally wak­ing up that this is a threat,” Kaine said. “So we’ll see what the plan is on it, but the no­tion that we may be fi­nally tak­ing our job ser­i­ously on it is something I’m hope­ful about.”

Kaine said that al­though he and the vast ma­jor­ity of Con­gress sup­port com­batting IS­IS, he dis­agrees with the ad­min­is­tra­tion that the pres­id­ent is with­in his au­thor­ity to do so. “I be­lieve the war is il­leg­al,” Kaine said Thursday. “I don’t think there’s a leg­al jus­ti­fic­a­tion for it. And I think the greatest danger we end up do­ing is al­low­ing the pres­id­ent to wage a war without Con­gress weigh­ing in.”

Kaine ad­ded that the pres­id­ent ac­ted ini­tially “to pro­tect Amer­ic­an lives” and cred­ited the White House for send­ing over an AUMF last year. “We haven’t done any­thing. So just the no­tion that maybe fi­nally there’s some in­terest in this, I find grat­i­fy­ing. But we’ll have to work through the de­tails,” he said.

Sev­er­al Demo­crats said they were un­aware of or hadn’t read the new AUMF lan­guage, but some greeted the op­por­tun­ity to open de­bate on the is­sue.

“I haven’t read it but I’m en­cour­aged by the fact that he’s not run­ning away from this is­sue any longer,” Sen­ate Minor­ity Whip Dick Durbin said of Mc­Con­nell. “The pres­id­ent has asked for this for a long time.”

Sen. Robert Men­en­dez, who helped to get a Demo­crat­ic draft AUMF through the For­eign Re­la­tions Com­mit­tee as chair­man in Decem­ber 2014, said that the new au­thor­iz­a­tion was news to him, but that he sup­por­ted bring­ing up the is­sue.

“I’m for the Con­gress vot­ing on an AUMF; of course it de­pends what the AUMF looks like,” Men­en­dez said Thursday. “I don’t want a blank check,” he said.

Cornyn, who in Decem­ber said that Re­pub­lic­ans would not present an AUMF of their own un­til the pres­id­ent out­lined a strategy, said that he non­ethe­less wel­comed de­bate on the is­sue.

“I don’t think we should be afraid of that de­bate, but we need a co­her­ent strategy from the pres­id­ent which we still don’t have and we also don’t need to tie the hands of the next pres­id­ent by re­strict­ing what the pres­id­ent can do,” Cornyn said.

“What I find kind of iron­ic about this is the pres­id­ent ap­par­ently thinks he has all the au­thor­ity he needs to do what he’s do­ing,” he ad­ded. “But I’m not afraid of the de­bate, I think it’s an im­port­ant de­bate to have, and cer­tainly the people we send in harm’s way need to know that the coun­try is be­hind them. So, thanks for telling me.”