We recently returned from the first congressional delegation visit to Saudi Arabia in well over a year, where we delivered the kingdom — including Saudi Crown Prince Mohammed bin Salman — the same message we have been spreading for months: Saudi Arabia has been an important strategic partner, but not one we will support at any cost.

We have been vocal critics of Saudi Arabia’s recent unacceptable behavior, and entered this conversation with open minds but skeptical ears. Over the course of our meeting, we engaged in a frank and direct dialogue with the crown prince on a number of topics. Our takeaway: Even as Saudi Arabia takes much-needed steps on key challenges, that process is incomplete — and tenuous. Saudi Arabia remains a nation of contradictions, with progress on some important issues matched by significant shortfalls on others.

Take national security, for example: The kingdom serves as the region’s key counterweight against the Iranian regime’s malign activities, and it is clear that Saudi security is not only a regional concern. Further, after spending time on board the guided-missile destroyer Gonzalez and after meeting with members of the U.S. military, the overwhelming message was that Iranian-backed terrorist proxy forces and the Iran Revolutionary Guard Corps continue to be a dangerous threat to U.S. interests in the region and beyond.

Our visit to the region illustrated the risks, but there is no better example of the importance of checking Iran’s behavior than the recent attacks on Saudi oil fields, which have been linked to Iran through open-sourced reporting and are consistent with the tense conditions we witnessed firsthand there.

Even though these attacks were not launched on our nation, they have increased the risk of American conflict with Iran — making it clear that the events that take place in the Middle East ripple out to impact our national security. Both the attacks and the increased risks associated with them threaten the 80,000 Americans living in Saudi Arabia. Because of these significant challenges to U.S. interests, our continued partnership with the Kingdom of Saudi Arabia is important as we seek regional stability.

However, the nation’s conduct in its war against the Houthis in Yemen has also been a destabilizing influence, exacerbating that nation’s civil war and the accompanying humanitarian crisis that has led to widespread starvation and the spread of infectious disease.

This suffering of the Yemeni people is not only an affront to our values that must to be addressed, but also a massive security risk. Millions of Yemeni citizens are starving and threatened by the cholera epidemic, increasing their risk of radicalization by terrorist groups.

We pressed Saudi and Emirati leaders on the importance of supporting a political process to end the war and providing the financial aid they have committed to address this humanitarian crisis. Both countries said that the outstanding funds will be released soon; we will remain unconvinced of their commitment until the assistance is not only provided, but properly administered to the Yemeni people in need.

We also discussed Saudi Arabia’s efforts to modernize, which would not only impact the kingdom; as a leader of the Muslim world, its progress will reverberate across the region. This was apparent particularly around women’s rights and reform of its guardianship laws. We met with a group of women leaders and politicians who expressed optimism at the new opportunities; and conversations with American diplomatic officials in the country confirmed that progress in this area is real, but reversible. That said, we expressed concern that the kingdom still has a long way to go.

For example, even though it is now legal for women to drive, several leading activists who pushed for these reforms are still imprisoned. We asked why these women remain in detention; we didn’t get good answers. As the crown prince talks about pursuing modernization, the continued imprisonment of these women, and other activists, undermines those efforts and must be corrected.

Lastly, we raised an issue that has brought about immense and justified global condemnation: the murder of Jamal Khashoggi, a Washington Post columnist and American resident, executed in Saudi Arabia’s consulate in Istanbul last year. We approached this subject directly and firmly, and the crown prince and other Saudi officials said they understood the impact this has had on the kingdom’s global reputation.

This murder flies in the face of the way global leaders must behave. We are able to write this column precisely because we live in a country that allows us the freedom to level criticisms without fear for our lives; Saudi citizens deserve the same opportunity. If Saudi Arabia seeks to transform into a 21st century leader, it cannot resort to barbarous tactics to quiet critics or dispose of dissidents.

Despite what we heard from the kingdom’s leadership, any serious improvement in our bilateral relationship requires justice and accountability on Khashoggi — delivered clearly, publicly and without equivocation. As a first step, this must include the Saudis holding accountable those involved in the murder, including Saud al-Qhatani, and the crown prince publicly acknowledging his responsibility.

Our visit illustrated to us both the demonstrable steps being taken in Saudi Arabia and the harmful vestiges of the past; only time will tell which will win out. Conversations with Saudi leaders and our experienced American diplomatic corps, military officials, and security officials provided reasons to believe that many of the most pressing issues creating a trust deficit between Saudi Arabia and the United States Senate can be addressed. But private assurances won’t make a difference; sustained public actions will.

Sen. Angus King, I-Maine, serves on the Intelligence and the Armed Services committees. Sen. Todd Young, R-Ind., serves on the Foreign Relations Committee.