Once that happens, she predicted, Iran and other regime defenders will begin to desert the regime, paving the way for renewed talks and a negotiated end to the conflict.

“If the Russians see, oh [the Americans] are serious now, they are going to arm them, [they’ll decide] let’s talk again about Geneva, let’s talk again about a political solution,” Rime Allaf, Jarba’s adviser for public diplomacy, told Al-Monitor in an interview at the opposition’s Washington-area hotel on Friday. “This is our way to the political solution, with the Russians, to get in and change their position. We understand that nothing is going to change without the Russians doing something about it.”

In an exclusive interview with Al-Monitor, a senior adviser to Syrian National Coalition President Ahmad Jarba said the conflict won’t end until Russia ceases to support President Bashar al-Assad. And without a shift in the balance of power on the ground, she said, that’s never going to happen.

The opposition’s main request — anti-aircraft weapons — is by now well-known. So is the US response to date: There’s no military solution to the conflict, and the weapons could fall into the wrong hands.

As the Western-backed Syrian opposition makes its rounds in Washington, it’s facing a recurrent question from skeptical lawmakers and administration officials: What, exactly, is the endgame?

“Assad cannot survive without the support of all these people. We think that the way to get this support away is to show that you have gone as far as you can, to convince Russia, which would then probably convince the Iranians that, you know, cut your losses — Assad is going. And we’ll see what happens next,” she said. “This is my personal analysis: I have always believed that when we reach that point, there are enough generals in the Syrian army, and enough people in state apparatuses, those who don’t have blood on their hands, who would say, you know, now is the time.”

Allaf made the case that portable anti-aircraft missiles — aka MANPADs — are America’s best bet to cut the conflict short and begin to reverse the surge in Islamist militants to the region.

“All we are asking for is to be able to defend ourselves against the monopoly of the air that Assad has,” she said. “Because if Assad’s planes are shot down by the Free Syrian Army [FSA], then first of all Assad will think twice before continuing this bombing campaign. And also, his sponsors will understand that actually it is not a green light anymore, they have to find a way to stop this.”

The campaign has been a tough sell on Capitol Hill.

“I don’t think now we have the support of our conference or the Democrats have the support of their conference to give them the kind of military hardware that they say they need,” Rep. Ileana Ros-Lehtinen, R-Fla., the chairwoman of the House Foreign Affairs panel on the Middle East and North Africa, told Al-Monitor after meeting with Jarba on Thursday. “There’s great apprehension about it falling into the wrong hands and folks selling it to the highest bidder.”

Allaf, who has also served as Jarba’s interpreter during his meetings with lawmakers and administration officials, said the meetings on Capitol Hill have been positive because they’ve allowed lawmakers to meet the opposition face-to-face for the first time. She predicted a lengthy campaign to try to change their minds and those of the American public, a mission facilitated by the administration’s decision this week to grant the opposition’s US offices a measure of recognition.

“Nobody expected we would walk out with gift bags of MANPADs on our way out,” she said.

She said the opposition was encouraged by President Barack Obama’s threat to use force after he concluded last year that Assad had used poison gas against civilians. That prompted Russia to support the United States in demanding that Syria turn over its chemical weapons, a scenario the opposition believes can be repeated if the administration arms the rebels in response to Assad’s use of barrel bombs against rebel-held areas.

“This is the only time there was a credible threat and the only time the sponsors of the Assad regime said, OK, you’ve got to give in somewhere,” Allaf said. “We think that the FSA getting the means to defend the population against those barrel bombs is also a message to the Russians that this is now unacceptable.”

Allaf added that anti-aircraft weapons will also enable the opposition to create an interim government on the ground, creating a viable alternative to Assad. Until now, she said, well-intentioned US support for education, health and administrative services has too often been buried under the rubble.

“We were asked, how come you’re not functioning more inside Syria?” she said. “We’re not, because the minute we establish ourselves anywhere, we’re bombed. On so many different perspectives, we need to eradicate, neutralize, ground the Assad air force to allow us to help our people.”

Allaf pushed back hard against the notion that arming the rebels would only prolong the conflict, or threaten to splinter the country.

“On the contrary, it’s the exact other way around: The recipe for 10 more years of war is not doing anything. It’s allowing Assad to think that he can continue getting away with it,” Allaf said.

“We are telling you now after the experience of three years of this regime with the developments in Syria, that continuing to do nothing is increasing the threat of terror, is increasing the chaos, is increasing regional instability because of the increased flow of refugees fleeing Assad’s bombs and barrel bombs. The more we do nothing, the more we are allowing this to happen.”

Even without US aid, she said, Assad’s foes will keep on fighting.

“The revolution is not going to die. The FSA is not giving up,” she said.

And the longer the war lasts, she said, the stronger sectarian tensions stoked by the Iran-backed Shiite militia Hezbollah and al-Qaeda-backed groups grow.

“More and more terrorists are coming, some at the invitation of Assad, some not,” she said. “The one party that has increased sectarian tensions and created this big muddle is the Assad regime.”

The opposition has been making that case repeatedly over the past week, in meetings with House and Senate leadership and members of key panels such as Armed Services, Foreign Affairs and Intelligence, as well as Secretary of State John Kerry. Jarba and other opposition leaders continue their Washington tour next week with a meeting with Obama himself as well as public events at the New America Foundation and Georgetown and Johns Hopkins universities.

An edited transcript of the interview follows:

Congress Pulse: This is the first official visit to Washington by the Syrian National Coalition. Why are you here?

Rime Allaf: We’re here because of what happened in Geneva. The coalition went to Geneva under pressure to try to negotiate a political solution, which would be basically the establishment of a transitional governing body.

From the beginning we knew that the regime was not serious, and we were told by our friends that ‘look, you go to Geneva and if it is indeed the regime which is to blame, then we will have a Plan B, we’ll have something different, we’ll have some pressure.’

So indeed we went, the regime was intransigent. And the promises we were made are what we are talking about today.

Congress Pulse: The elections in Syria are going ahead, and the Syrian government just negotiated a cease-fire with opposition forces on the ground in Homs. What is the strategy, beyond lobbying Washington for more arms and aid? How does this end?

Allaf: The regime today believes that international apathy should be interpreted as a green light to continue doing what it wants. The elections it is holding is not only obviously a farce and obviously an insult to the Syrian people - it is really also an act of defiance to the international community.

This is the message we are giving in Washington: We still think that the crisis can only be solved politically. But in order to for us to reach that political solution, we have to A) Give a message to Assad and his sponsors, and B) Change the balance of power on the ground.

As long as Assad continues unopposed to carry on with the bombing and to carry on running his military campaigns with the help of Hezbollah, with the help of the Iranian revolutionary guards, and with the help of the Iraqi militias - as long as he’s unopposed in doing that, there is no end in sight.

Congress Pulse: What kind of aid could prevent that?

Allaf: We have understood a long time ago, that a no-fly zone was not possible, which is a pity because had a no-fly zone been established we would not be where we are today.

All we are asking for is to be able to defend ourselves against the monopoly of the air that Assad has. Because if Assad’s planes are shot down by the Free Syrian Army, then first of all Assad will think twice before continuing this bombing campaign. And also, sponsors will understand that actually it is not a green light any more, that we need to find a way to stop this.

Fankly, there are countries of the Gulf who have these weapons but who for the time being have been asked by the US not to deliver them. Our message was, we would be grateful if you could just give your approval. That’s the way the world works: The US needs to say OK.

Congress Pulse: Is the strategy then to continue the armed struggle indefinitely? What is being offered by the US and others does not seem likely to tilt the balance in your favor.

Allaf: On the contrary, it’s the exact other way around. The recipe for 10 more years of war is not doing anything. It's inaction. It's allowing Assad to think that he can continue getting away with it.

What happens if we get those antiaircraft weapons? At least we have a fighting chance. At least we can limit the damage and protect civilians. It is our job to try and get political support, to bring some form of protection to these people.

But strategically, we think that there is an international will to put the slaughter/conflict to an end. Then we might see a different position from the Russians. I remind you that the only there was a response, some kind of a response was when there was the threat of a military strike after the chemical weapons massacre.

Assad cannot survive without the support of all these people. We think that the way to get this support away is to show that you have gone as far as you can, to convince Russia, which would then probably convince the Iranians that, you know, cut your losses - Assad is going.

Congress Pulse: How do you see Syria evolving if you don't get more support? Does the rebellion peter out? Wouldn't that put an end to the influx of foreign would-be jihadists, who have pouring in from across the Middle East and, increasingly, Europe?

Allaf: The revolution is not going to die, the FSA is not giving up. And on the contrary, we are in fact inviting more terrorists to the region. Assad’s hold on power is a magnet for more terrorism, and it will not remain contained in Syria – that’s for sure.

Already we’re seeing havoc being created in Iraq. I don’t know how much you’re willing to bet that Lebanon is going to stay very quiet when now you’ve got a million Syrian refugees. The south of Turkey is not very quiet at the moment. The entire region is boiling.

We are telling you now after the experience of three years of [war], that continuing to do nothing is increasing the threat of terror, is increasing the chaos, is increasing regional instability because of the increased flow of refugees and the refugees are fleeing Assad’s bombs and barrel bombs.

Congress Pulse: What is your vision for a future Syria, once Assad is gone? And how do you convince policymakers that you're united enough to be a viable alternative?

Allaf: The coalition, and I believe the vast majority of people in Syria, are looking for that solution which would get the Assad clan out. But we want to keep our institutions together. We are very, very determined to keep the unity of the Syrian army and to make sure the FSA and regular army remain a cohesive body and that they maintain the security of the state once those murderers are gone.

We in the Coalition represent a number, a wide spectrum of opposition voices, I think this is a credit to our belief and to our yearning for a democratic system in Syria. Everybody is allowed to say what they want. Sometimes it might give the impression, 'oh, you are not united,' but this is not what we want to show; we want to show on the contrary that we are a coalition.

This is why Mr. Jarba brought such a large delegation. The point is we’re trying to show you that we have different voices, but the main message is the same: We do need help. And that help is a limited help.

Congress Pulse: Do you think you've made any progress during this trip?

Allaf: Nobody expected we would walk out with gift bags of MANPADs on our way out. But we think these meetings are positive because this is the first time they hear directly from the coalition – where we stand, who we are, what we’ve been doing, who we’ve been fighting. And we are telling them, we are on the same side on terrorism.

For the first time, American lawmakers have a clear representation. We don’t expect them to go home and say, ‘you know, I’ve changed my mind’. But at least we were told by several lawmakers: ‘Thank you, we heard your message, we’re going to be discussing it’.

Also, being a foreign mission from now on will open the door to more, to easier communication between us. We’re really seeing this trip as a very positive development. Nobody thinks we were going to leave Washington with extra suitcases.