WASHINGTON >> As he prepares for a long trip to Asia, President Barack Obama has opened an intense campaign to promote his new trade agreement with 11 other Pacific Rim nations as a way to lower tariffs, open world markets and build middle-class jobs.

The agreement, known as the Trans-Pacific Partnership, is the economic cornerstone of Obama’s drive to refocus U.S. foreign policy on Asia. The president has made it the center of attention this week in advance of his departure Saturday for the Group of 20 summit meeting in Turkey, followed by stops in the Philippines and Malaysia.

To promote the accord, Obama in the past few days has published two op-ed articles and a letter to online business owners who use eBay. He has also invited national security figures from both parties, led by two former secretaries of state, James Baker and Madeleine Albright, to join him at the White House on Friday to talk up the merits of expanding trade with Pacific Rim nations.

"The Trans-Pacific Partnership will help generate higher wages, safer workplaces, fairer competition, and a cleaner environment — standards I will highlight as I travel from the G-20 to the Philippines and Malaysia," Obama said in an article published in the Financial Times.

"If America is going to continue to lead," he wrote in his letter to eBay business owners, "we have to make it easier for entrepreneurs like you to sell what you proudly make here in some of the fastest-growing markets around the world."

The trade pact would set rules of the road for trade and investment between the United States and Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam, countries that together represent about 40 percent of the world economy. The government of the Philippines has indicated that it wants to join as well. China is not part of the pact.

The agreement has come under fire especially from liberal activists, labor unions and congressional Democrats who complain that it would not do enough to enforce high environmental and workplace standards overseas and would result in more manufacturing jobs’ being exported to low-wage countries. Among those opposing it are the leading Democratic presidential candidates, former Secretary of State Hillary Rodham Clinton and Sen. Bernie Sanders, I-Vt.

Republican congressional leaders have been more supportive, pushing through fast-track authority last summer so that Obama can submit the final pact for an up-or-down vote rather than subject it to possible amendments.

Still, since the text of the trade agreement was released last week, congressional Republican leaders, such as the new House speaker, Paul Ryan of Wisconsin, have withheld judgment, and some Republican presidential candidates, led by Donald Trump, have denounced it.

"The TPP is a horrible deal," Trump said at this week’s Republican debate. "It is a deal that is going to lead to nothing but trouble. It’s a deal that was designed for China to come in, as they always do, through the back door and totally take advantage of everyone."

He added that he was "a free trader, 100 percent" but that "we don’t have smart people making the deals."

Sen. Rand Paul of Kentucky, one of his opponents on the debate stage, suggested that Trump did not fully understand the agreement, noting that China was not part of it.

"There is an argument that China doesn’t like the deal because in us doing the deal, we’ll be trading with their competitors," he said.

Obama hopes to show bipartisan support for the trade deal with an event at the White House on Friday. In addition to Baker, who was the top diplomat for the first President George Bush, and Albright, who had the same role for President Bill Clinton, Obama will host Brent Scowcroft, who was national security adviser to Bush and President Gerald Ford, and Adm. Mike Mullen, who was chairman of the Joint Chiefs of Staff under President George W. Bush and Obama.

The gathering is reminiscent of Clinton’s campaign to pass the North American Free Trade Agreement, when he recruited presidents of both parties, including Ford, the first President Bush and Jimmy Carter, to lobby on its behalf.

"TPP is central to our vision of the region’s future and our place in it," Susan Rice, Obama’s national security adviser, told reporters Thursday. "And one of the president’s top priorities is to secure passage of TPP through Congress and to implement the agreement."

It is rare for the president to write, or sign, so many columns on the same topic in just a matter of days. But in choosing the Financial Times, Bloomberg View and eBay, the White House was targeting business audiences in hopes of bolstering support for the pact to counter the muscle of organized labor.

"Not every American will support this deal, and neither will every member of Congress," Obama said in his column for Bloomberg View. "But I believe that in the end, the American people will see that it is a win for our workers, our businesses and our middle class.

"And I expect," he added, "that after the American people and Congress have an opportunity for months of careful review and consultation, Congress will approve it and I’ll have the chance to sign it into law."