The White House appears poised to end a ban on arms sales to Vietnam in time for a landmark visit by President Barack Obama later this month, despite misgivings from some lawmakers and human rights advocates.

The step would carry crucial symbolism in the growing contest for influence between China and the United States in the Western Pacific and also for America’s relationship with Hanoi that has come full circle since the dark days of the Vietnam War.

Anxious about China’s aggressive moves to assert its territorial claims in the South China Sea, Vietnam’s government has pressed repeatedly for an end to the prohibition on U.S. arms exports, which would permit Hanoi to buy high-tech American military hardware such as sophisticated radar or surveillance aircraft. Two years ago, Washington partially lifted the ban to permit the sale of weapons related to “maritime security.”

But while the U.S. Defense Department views the potential step as a key strategic move to counter China, human rights groups and some U.S. senators worry the White House will give up vital leverage without getting sufficient concessions in return.

Senators from both parties, including Sen. Patrick Leahy (D-Vt.), have voiced objections and reservations over lifting the ban and argue the administration should hold off on any dramatic gestures without more evidence of progress on civil liberties in a country that routinely arrests and beats dissidents.

Although Leahy has long supported broadening U.S. relations with Vietnam, he “feels quite strongly about freedom of expression” and wants the administration to explain what Vietnam is expected to do on human rights issues if the United States allows lethal arms sales, said his aide, Tim Rieser.

The United States “needs to make clear, as we do when we give aid to other governments, that we’re not going to write a blank check to the Vietnamese military,” Rieser told Foreign Policy.

During a single week in March, Vietnamese authorities convicted seven bloggers and activists and sentenced them to prison. The country’s Communist Party commands a sweeping monopoly on power, and Vietnam remains one of the most repressive regimes in the world, according to Human Rights Watch.

“Lifting the ban on lethal arms sales to Vietnam would be premature and undeserved at this time, unless Hanoi takes critically needed steps to address its poor human rights record,” said John Sifton, Asia Advocacy director for Human Rights Watch.

The White House has been debating the move in recent weeks, administration officials and congressional aides told FP on condition of anonymity. U.S. Defense Secretary Ash Carter has already come out in favor of the move, in remarks at a Senate hearing last month that took lawmakers by surprise.

The final decision will hinge in part on the outcome of talks on Monday and Tuesday in Vietnam led by two senior State Department diplomats: Assistant Secretary of State Tom Malinowski, who oversees democracy, human rights, and labor issues, and Assistant Secretary of State Daniel Russel, who runs the agency’s East Asian and Pacific bureau.

The State Department said in a statement that Malinowski would be urging Hanoi to “release political prisoners without condition” and carry out other reforms in line with the country’s international human rights obligations.

Vietnam has released about two dozen political prisoners over the past year, reducing the number known to be behind bars from an estimated 125 to 100 — though rights groups say it also has stepped up harassment of activists through beatings.

Analysts say the government in Hanoi may have released the dissidents to bolster its position during talks on the Trans-Pacific Partnership trade agreement, which could offer new markets for Vietnam’s growing economy. Under the trade deal, Hanoi agreed to a major change in its labor laws that would allow for independent trade unions for the first time.

It remains to be seen if Vietnam will follow through on its commitment on labor reforms. But when Malinowski helped make the case for the trade agreement last year in a commentary, he cited the ban on arms sales as a source of continued leverage that would stay in place even once the trade negotiations were over.

The administration has not offered up that argument recently amid preparations for the president’s visit to Hanoi later this month, which will mark the first by Obama to Vietnam. He is also due to visit Japan on the same trip, and there is growing speculation the president will be the first U.S. commander in chief to set foot in Hiroshima.

It’s not the first time that the administration’s diplomatic approach and negotiating tactics have been portrayed as too conciliatory to repressive regimes. Citing overtures to Cuba and Iran, some critics in Congress have accused the White House of delivering major concessions at the outset without demanding sufficient reforms or changes up front.

Senate Foreign Relations Chairman Bob Corker (R-Tenn.) favored the 2014 partial lifting of the arms sales ban but has reserved judgment on any wholesale end to the prohibition for Vietnam.

“Any more expansive shift in policy will require further review and must align with U.S. interests, including the desire for progress on human rights,” an aide to Corker said.

However, Maryland Sen. Ben Cardin, the committee’s top Democrat, said he is open to rescinding the ban if human rights issues are taken into account.

“While I agree it is critical that the United States build a strategic, multifaceted partnership with Vietnam, we must take care to ensure that any potential arms sales are appropriate to our bilateral relationship and would support regional stability,” Cardin told FP.

The Maryland senator traveled to Vietnam in 2014 and raised his concerns about human rights with several senior officials, including the prime minister.

When asked about a possible change in policy on Vietnam, State Department spokeswoman Katina Adams said “human rights remain an essential element of our policy with Vietnam.”

She added: “Ahead of the president’s trip, we continue to review our policies in parallel with the development of our bilateral relationship with Vietnam.”

Supporters of ending the arms ban say that Vietnam has made progress over time on rights issues and that its record compares favorably to some other U.S. partners accused of horrendous abuses, such as Saudi Arabia or Egypt.

“Human rights is not an absolute. We judge it based on a relative scale,” said Gregory Poling, a fellow at the Center for Strategic and International Studies. “We reward those who are improving and punish those who are backsliding,” and Hanoi has been on an upward trajectory, he said.

The Vietnamese recognize they must coexist with China, the looming neighbor on their northern border, Poling said. “But they are desperate to get as much strategic room to maneuver as they can. The U.S. is key to that,” he said.

The “prime motivation” behind Vietnam’s request to lift the arms restrictions is more political than military, said Carl Thayer, an expert on Southeast Asian security at the University of New South Wales and the Australian Defence Force Academy.

Vietnamese hard-liners who back the regime note that despite plenty of diplomatic overtures between Hanoi and Washington of late, many government officials still fear the United States seeks a quiet revolution through its push for human rights. Combined with lingering resentment over U.S. efforts to address wartime use of the toxic chemical mixture Agent Orange, maintaining a “discriminatory” policy on arms sales looks to Hanoi like punitive politics, Thayer said.

That said, in the context of rising tensions in the South China Sea, the United States has sought to improve the ability of its allies and partners to patrol their own waters, especially when confronted with a large and growing Chinese maritime force.

So far, Vietnam has not given Washington a big wish list regarding future arms sales, and an end to the ban would not open the floodgates for big defense deals, experts said.

To date, U.S. military assistance to Vietnam — which is limited to the Coast Guard — has consisted of a few old, small patrol boats. And Vietnam’s major military equipment — whether advanced submarines frigates or multirole fighter jets — is Russian-made and will almost certainly stay that way. Shifting to U.S.-manufactured weapons would be too expensive at this point.

One potential area of cooperation, as between the United States and India, could be access to more advanced defense technologies.

Carter, the latest Pentagon chief to make a point of traveling to Vietnam, said in a visit to the country last June that “our countries are now committed for the first time to operate together, step up our defense trade, and to work toward co-production.”

In a joint vision statement agreed upon during Carter’s stop in Hanoi, the two governments called for cooperation on defense technology. Vietnam, like other countries in the region, wants to upgrade older weapons systems and acquire radar, surveillance drones, or reconnaissance planes — such as P-3 Orions or P-8 Poseidons — to help them track Chinese ships and submarines, experts said.

“Vietnam would like to see some technology transferred. This is an evolving issue and the one with the most promise,” Thayer said.

U.S. officials have also privately spoken of the possibility of having American naval ships once again operate out of strategic Cam Ranh Bay, which served as a hub for U.S. forces during the Vietnam War. But Hanoi has yet to endorse the idea publicly.

“I do not think that China’s reactions to arms procurements by Vietnam are all that decisive in Vietnam’s calculations,” Thayer said. “Vietnam is more concerned about giving the U.S. a presence, say at Cam Ranh, and how China would react to that.”

Apart from warning against ending the arms sales ban, human rights advocates have appealed to the White House to use the president’s visit to Vietnam to highlight the plight of political prisoners and bloggers in a manner similar to Obama’s recent groundbreaking trip to Cuba.

In an April 27 letter to the president, Human Rights Watch urged Obama to make time during his visit to meet with former political prisoners and civic activists, hold a joint press conference with his Vietnamese counterpart, Gen. Tran Dai Quang, and deliver a speech that highlights the importance of fundamental rights to the future of the relationship between the two countries.

“Many in Vietnam are looking to you and the United States to stand up for the ideals they are taking great risks to promote,” the letter said.