An Iraqi woman casts her vote in Iraq's parliamentary election (ballot-L) and in a postponed Kurdish regional election (ballot-R) in the Iraqi city of Kirkuk on April 30, 2014. (Marwan Ibrahim/AFP/Getty Images)

Joe Biden is vice president of the United States.

In recent months, the terrorist group known within the U.S. government as the Islamic State of Iraq and the Levant (ISIL) has seized significant territory inside Iraq, exploiting sectarian divisions and political mistrust that sapped the strength of Iraqi forces. ISIL seeks to rip Iraq apart in its quest to establish a caliphate. But Iraq’s communities have started to unite in pushing back.

Since more than 13 millionIraqis cast their ballots in April despite threats from ISIL to kill anyone who voted, Iraqis have convened a new parliament, selected a speaker and president and designated a new prime minister, Haider al-Abadi, to form a new government.

These steps are meaningful because they show that Iraqis have begun to understand that they must rise above their differences. And that, when they do, they can succeed — not only in uniting the country but in defeating ISIL.

There is no negotiating with ISIL. We have seen its appalling murders of U.S. journalist James Foley and countless other innocent people, its cruelty and its fanaticism.

But even if there were no ISIL, Iraq’s survival would still depend on the ability of Iraqis to set aside their differences and unite in a common effort. Iraq’s security would still depend on addressing the alienation that fuels extremist movements and convincing Iraqis that their needs can be met through the political process rather than through violence.

In the past few weeks, President Obama has spoken with Abadi and I have spoken to each of Iraq’s incoming and outgoing leaders. We have come away encouraged that they recognize that years of political deadlock and discord must end. As Abadi wrote the other day, the “challenges we face are immense but we will overcome them by uniting. Raging storms may be ahead but we will face them together as one nation.”

For Iraq, success will require genuine compromise from all sides and a new government in Baghdad capable of responding to the needs of all of Iraq’s communities. We cannot want that more than Iraqis do. Unless Iraq can do this, no amount of outside intervention will matter — nor will it continue indefinitely.

That’s why government formation is so critical. As prime minister-designate, Abadi is working to put forward a new lineup of cabinet ministers and a road map that will set the agenda for Iraq’s new government. We are encouraging Iraqi leaders to complete this process as soon as possible. We are hopeful that the road map Iraq’s parliament endorses will sketch a vision for harnessing the resources of the state to benefit all communities and take the fight to ISIL.

We are also encouraging Iraq’s neighbors to refrain from fueling sectarian divisions, which only plays into ISIL’s hands, and instead to treat this shared challenge as an opportunity to begin a new chapter in their relations with Iraq and with each other.

Iraq’s security efforts, like its politics, must harness the energy and cooperation of all communities. This new spirit of cooperation was evident this week in northern Iraq, where Iraqi and Kurdish forces worked together to retake the Mosul dam from ISIL. Notwithstanding U.S. support, this operation could not have succeeded without cooperation between the Kurdish pesh merga and Iraqi security forces. This was the first joint operation of its kind, and we believe it is a model to build upon.

Another approach that is emerging is a “functioning federalism” under the Iraqi constitution, which would ensure equitable revenue-sharing for all provinces and establish locally rooted security structures, such as a national guard, to protect the population in cities and towns and deny space for ISIL while protecting Iraq’s territorial integrity. The United States would be prepared to offer training and other forms of assistance under our Strategic Framework Agreement to help such a model succeed.

It will ultimately be up to the Iraqis to define their future under their own constitution, but we are encouraged that a serious debate about that future has begun. As Iraqis continue to make progress, we are prepared to further enhance our support for Iraq’s fight against ISIL — and will call on the international community to join Canada, Australia and our European allies in doing the same.

ISIL is far from invincible. Its ideology is rejected by most Iraqis. It establishes order not through consent but through fear. It has destroyed ancient religious sites, enslaved women and girls and brutally executed many of the very Sunnis it claims to speak for. ISIL has no legitimate cause or grievance to espouse. And as we saw at the Mosul dam, when its fighting strength is eroded, it can be routed by local forces without U.S. boots on the ground.

This is a fight that Iraq, with help from America and the world, can and must win. We all have a stake in empowering moderates in Iraq to prevent a terrorist state from taking root in the heart of the Middle East. The threat, of course, is not confined to Iraq. Addressing it will also require continued support for our partners in Jordan, Lebanon, the Syrian opposition and others to counter ISIL and address the flow of foreign fighters to and from the battlefield.

As Iraqis begin to unite in their resolve against ISIL, we must be prepared to do the same. We will continue to consult closely with Congress about our strategy in Iraq and the region when it comes to ISIL and the security of our people. This will be a long-term challenge. It is one that our partners around the world, with our support, have no choice but to take on and win — starting in Iraq.