Today, US President Barack Obama will host the leaders of the ten countries that make up the Association of Southeast Asian Nations (ASEAN) for a summit in Sunnylands, California – the first meeting of its kind on US soil.

The timing of this meeting is highly strategic. Mr Obama hopes to bolster the future of the controversial Trans-Pacific Partnership (TPP) trade agreement, as well as secure a bulwark against Beijing’s advances in disputed territory in the South China Sea.

As part of his administration’s larger “pivot to Asia”, Mr Obama hopes to re-emphasise relations with a key emerging region – one which has remained open to the world and has seen substantial economic gains over the past decade.

Yet despite these promising developments, there is serious trouble on the horizon. The past two years have witnessed a disturbing deterioration of democracy and human rights protections throughout Southeast Asia.

From Thailand to Malaysia to Laos, political leaders have pushed back against the democratic aspirations of their people through military takeovers, political intimidation, show trials or a one-party state.

In my own country, Cambodia, democracy and human rights are seriously threatened with the further deterioration of rule of law. Physical attacks and the use of the courts are tactics to silent government critics.

These tactics include cases against the minority leader, Sam Rainsy, and opposition lawmakers on trumped-up charges. Of more serious concern is the use of armed forces and hired security guards to crackdown on peaceful public protests.

With the world becoming more dangerous and unpredictable, President Obama might be tempted to de-emphasise the significance of these developments at the upcoming summit, focusing instead on strengthening bilateral economic and security ties.

But for the summit in Sunnylands to have any lasting impact, the regional erosion of democracy cannot take a backseat.

Instead, the meeting should be seized as an opportunity for President Obama to send a clear message to Southeast Asian leaders that respect for human rights, free elections and basic human dignity are in the interest of their governments, as well as the long-term stability of the region. It represents an opportunity for Mr Obama to endorse a more democratic ASEAN by openly discussing these concerns.

Supporting democracy and accountable leadership in South East. Asia is a smart investment for the United States.

Legitimising a facade of democracy or accepting outright dictatorship will undermine US efforts in Southeast Asia, allowing China to cultivate influence over autocratic leaders who see Beijing as an easy source of strings-free aid.

But by listening to the voices of the people of ASEAN, who seek dignity and accountability from their governments, Washington will be able to deepen its commitment to the region and ensure sustainable partnerships that do not rely on particular political personalities remaining in power.

Cambodia can be a strong US partner with a change of leadership. When he sits down with Prime Minister Hun Sen in Sunnylands, President Obama must be unequivocal that the Cambodian government cannot continue to silence opposing views through arrest warrants and imprisonment.

The next elections must be free and fair. All candidates must have the right to be in the country to campaign and be given a fair chance to be elected.

This is the opportune moment for the United States to use its leverage to send a message that the trans-Pacific relationship is more than just economic. Its future depends on universal respect for rights and dignity, not merely trade agreements and security cooperation.

Free trade with no rule of law or human rights standards will only benefit the large multinationals at the expense of ordinary citizens on both sides of the Pacific. It threatens to weaken civil society, trade unions and small businesses, the true backbone of economic growth for all.

Efforts must be made to protect labour rights and ensure a living wage for all workers. All stakeholders, including governments, local civil society, labour unions and corporations, should be able to sit at the same table to work towards solutions.

We must also recognise and account for the unique challenges women face in countries like Cambodia, where more than 90 per cent of garment workers are women, primarily from rural areas with little or no education.

Fair trade that affords all ASEAN workers dignity and opportunities should be the goal. To achieve this, the United States needs ASEAN partners that respect human rights, the rule of law and democratic principles.

Standing on the side of democratically elected leaders and popular movements for change would give the US more credibility among Southeast Asian publics and demonstrate that its support for democracy and human rights is more than just empty talk.

Mu Sochua is a member of parliament for the Cambodia National Rescue Party.