The new U.S. ambassador to Haiti, Pamela White, presented her credentials on Friday to Haitian President Michel Martelly.

White is a career diplomat who previously served as ambassador to The Gambia before she was tapped to head the U.S. embassy in Port-au-Prince. This will mark her second stint in Haiti. She first worked in the country from 1985-90 on behalf of the U.S. Agency for International Development.

“I never forgot my deep and abiding admiration of the people of Haiti,” White, who has 35 years experience in diplomacy, said in a statement.

White replaces Ken Merten, also a career diplomat, who completed his tour last month after arriving in Haiti in 2009. It was Merten’s third diplomatic posting in Haiti and his most challenging, as he saw the country through the January 2010 earthquake, a deadly cholera outbreak and controversial presidential elections.

“While I don’t necessarily want to be remembered as the American ambassador who was only there for the earthquake, I do think that was a huge accomplishment,” Merten, whose next posting will be as U.S. ambassador to Croatia, said in a recent Miami Herald interview.

In the early days after the quake, Merten, who speaks fluent Creole, went on radio in Port-au-Prince, pleading with Haitians to remain calm and informing them help was on the way.

“We, the U.S., the Haitians, [the U.N. peacekeeping mission], we did a really good job of talking to the people, letting them know what’s coming and getting them food, getting them water,” he said.

Merten then faced his next big challenge — and criticism — as the U.S. took a lead role in Haiti’s presidential elections, which erupted into a months-long crisis and sparked days of violent protests amid allegations of voter fraud.

The U.S. embassy, which issued a statement denouncing the initial first-round results that had President Michel Martelly initially finishing third, was accused by critics of overstepping its bounds and trying to engineer the outcome.

“I know intellectually and in my heart that is not what we did,” Merten said. “There is always in Haiti an oversized belief in what the American embassy can do in Haiti. So I understand where that comes from, but it’s simply not the case…. Our interest was in the process, not in a person.”

Merten said he does not regret the U.S.’s financial investment in the elections, and its role in ensuring “that people felt that their vote was respected.”

For her part, White inherits a situation that remains complex. Aid disbursement and post-quake reconstruction remain slow. Last month Ecuador and Brazil both said they would assist Haiti with reviving its disbanded army, despite insistence by the U.S. and others that Haiti should focus on strengthening its national police.

Meanwhile, efforts to create a permanent electoral council to carry out elections have been stymied by political disagreements and gridlock.

Prime Minister Laurent Lamothe and Martelly, who recently staged a three-day carnival in Port-au-Prince, have brought a new energy to the country, promoting it on the global stage. But each has been hindered by ongoing political bickering and internal conflicts.

The next six months, Merten and others say, are critical to Haiti’s progress. Merten says he’s optimistic.

“We are at a moment now where Haiti could be moving forward in a pretty good way as it was, frankly, right before the earthquake,” he said. “Things were moving in a positive trend line for Haiti in terms of business, general stability, security. We are in a similar place now.”

“You have a government that is serious about exercising its authority in certain areas, whether it’s car inspections to picking up trash to working with foreigners to coordinate what development projects are going on.”