Today, I arrive in a thriving Israel, but there is trouble in the neighborhood. From Egypt to Syria and beyond, the Arab revolutions have been a mixed bag for Israel. Some in Washington look at the challenges in the new Middle East and advocate disengagement. I strongly disagree. We cannot stand up for America’s interests—or Israel’s—from the sidelines. Now is the time to roll up our sleeves and engage in support of our ideals, values and interests.

The U.S.-Israel relationship is stronger than it has ever been. And our support is growing with investments in the Iron Dome missile defense system, training and joint military exercises, intelligence cooperation, and partnerships in research and development for military equipment.

Senior U.S. and Israeli defense officials will tell you our security cooperation has never been better—and for good reason. Today, America and Israel face a region in turmoil and increasingly complex and pressing threats.

At the top of the list is Iran. Its provocative actions threaten not only U.S. national security and regional stability, but pose an existential threat to Israel. Iran continues to export terrorist activity directly and through proxies, like Hezbollah. It actively supports the Assad regime in Syria with fighters, arms and petroleum. And its drive for nuclear weapons is accelerating.

We cannot allow the Iranians to continue to stall through talks while simultaneously bringing hundreds of new centrifuges online, which is why I have led the efforts in the U.S. Senate to impose crippling sanctions that have cut Iran’s oil exports in half. We need to toughen those sanctions to further reduce purchases of Iranian oil. We need to prevent Iran from buying dual use items on the international market that benefit its nuclear program and we need to explore options for increasing military pressure on Iran to make clear that we will take all necessary steps to prevent a nuclear capable Iran, including the military option if all others fail.

Next door in Syria, one of the greatest humanitarian crises in the world is unfolding. Vital U.S. and Israeli interests are at stake, including the stability of the Middle East, loose chemical weapons, and the danger that Syria becomes a safe haven for extremists. The United States must play a role in tipping the scales toward moderate opposition groups and work to build a free and stable Syria.

That was the motivation behind the legislation I introduced in the U.S. Congress, which was passed by the Senate Foreign Relations Committee last week, that gives the Administration more flexibility to provide humanitarian aid; creates a transition fund that supports institution building in a post-Assad Syria; imposes sanctions on arms and oil sales to Assad; and provides authorities to arm moderate elements of the Syrian opposition.

I know that there are real concerns about providing arms to the opposition, and I understand those concerns. But the choice is not between arming and not arming. The choice is between responsibly stepping in or leaving it to others who will simply arm the extremists.

Egypt also presents a dynamic set of challenges. We must encourage Egypt to work with the IMF to stabilize its economy and pursue longer-term institutional reforms that will allow democracy to gain a foothold. At the same time, we will make clear that U.S. aid to Egypt is not a blank check, which is why Congress has made our assistance to Egypt contingent on upholding the 1979 Peace Treaty.

As for the peace process, it has always been my position that we must move toward an acceptable two-state solution. We have seen new momentum with Secretary Kerry’s personal diplomacy. The rekindling of the Arab Peace Initiative and new investments in the Palestinian economy are positive steps. I am hopeful that we can resume negotiations and avoid distractions and grandstanding at inappropriate venues like the United Nations.

We cannot know what the future will hold. But amid the turbulence in the region today, one thing remains constant: the strong, unshakable and rock-solid relationship between the United States and Israel. The threats we face may test our resolve, but they will never test the friendship that binds us in a strong and lasting alliance.

U.S. Sen. Robert Menendez, a Democrat from New Jersey, is chairman of the Senate Foreign Relations Committee.