Workers at the largest US ports who can make over $100,000 are negotiating a contract for the first time in 7 years. Here's the history of one of America's most powerful unions.

In a speech at the port, Biden addressed the supply-chain crisis and thanked dockworkers for their efforts in processing over $294 billion in trade last year — the most in the port's 115-year history.

Since the pandemic and the resultant supply-chain crisis, the crucial role of dockworkers has become increasingly apparent.

The Port of Los Angeles and the Port of Long Beach have been the sites of historic backlogs since the pandemic started.

Last year, nearly half a million shipping containers waited outside the port for weeks on end as dockworkers hustled to move more goods than any year on record. Before the pandemic, the ports never saw a backlog greater than a handful of ships, Kip Louttit, the executive director of the Marine Exchange of Southern California, previously told Insider.

In recent months, the backlog has slightly decreased, but labor negotiations could throw a wrench in the port that handles over 42% of all US trade with Asia.

Former President Barack Obama's administration also stepped in to mediate the labor negotiations in 2015.

The ILWU represents over 22,000 West Coast port workers across dozens of locations.

The union is known as one of the most powerful in the US. It has a history that dates back to the early 1900s.

Though, both the union and the ILWU and the Pacific Maritime Association (PMA), which represents about 70 employers, said on Tuesday that they do not expect to reach a deal before the workers' contracts expire on July 1.

The negotiations have been ongoing since late May. On May 6, Labor Secretary Marty Walsh said on Bloomberg Television that the White House does not plan to intervene unless it has to.

The over 7,000 longshoremen represented through the International Longshore and Warehouse Union (ILWU) that work at the Southern California port are paid over $100,000 a year and receive free health insurance and full pensions, according to a book from The Wall Street Journal's Christopher Mims, "Arriving Today: From Factory to Front Door — Why Everything Has Changed About How and What We Buy."

In 2015, Los Angeles Times reported that foreman and managers at West Coast ports can make over $200,000 a year, while bosses can earn more than $300,000. Though, many of the workers at the ports are part-time workers who do not enjoy the benefits of the union and receive a starting pay of about $25 per hour.

The very first union in the US for waterfront workers was formed in 1864 in the port of New York. Between 1881 and 1905 there were more than 30,000 strikes, according to the International Longshore Association (ILA).

The ports were filled with new immigrants who were easily "exploited," per the ILA.

But, the West Coast ports didn't begin to unionize till the early 1900s.

The union said employers imported African American workers to act as strikebreakers or diverted cargo between the ports to disrupt major strikes, including ones in 1916, 1919, and 1921.

"These were the days of the shape-up, kickback, blacklist, goon squads, wage cuts, speed-up and staggering accident rate," the ILWU said on its website.

West Coast dockworkers revived a charter with the ILA in 1933, but this time they made it a single unit across the Pacific Coast.

They called for a hiring hall that would be controlled by the union instead of employers, a six-hour work day, and higher hourly wages, per ILWU.

The union workers gradually broke off from the ILA, which now represents East Coast workers, to form the ILWU in 1937.

On May 9, workers across every West Coast port walked out.

The strike continued for 83 days. Workers published a series of papers called "The Waterfront Worker" that highlighted some of their struggles.

Within days, employers responded to the walkout by hiring strikebreakers. They would house them on nearby ships or in secure compounds, and transport them to the work site using police protection.

When strikers attacked the police transport on May 15 in San Pedro, California, police fired on them, killing longshoremen Dick Parker and injuring several others.

The Roosevelt Administration attempted to broker a deal between the union and employers, but workers continued to strike.

Several other unions and workers across the maritime industry and supply-chain showed support for the strike.

President Franklin D. Roosevelt agreed to send troops to stop the strike in July as he had decided that "we are now in a state of armed hostilities."

Police shot tear gas at workers on the picket line on July 5, 1934 in San Francisco, California. Strikers threw cans and attempted to overturn police vehicles, according to reports.

The ILWU said two workers were shot and killed during the melee, and a total of six were shot or beaten to death by police or other citizens during the course of the strike.

The events led to a San Francisco General Strike from July 16 to 19, during which time 40,000 workers across the city walked out of work.

The strike ended on July 30 and an agreement was reached in the fall of 1934. To this day, ILWU workers celebrate July 5 as a turning point in their labor efforts, the ILWU said.

Former President Harry S. Truman signed an executive order in 1946 that allowed for US troops to seize and operate the railroads ahead of a national strike.

Following World War II, over five million Americans were involved in labor strikes between 1945 and 1946.

The railroad strike left only 100 out of 175,000 trains in the US running. In response, Truman called for emergency temporary legislation to allow him to draft the workers who were striking into the Armed Forces. Before the legislation could be passed the strike ended.

The same year the ILWU helped form the Committee for Maritime Unity (CMU), an association designed to unite waterfront workers across the various unions. Truman told the CMU if they were to strike, similar measures would be taken, according to the ILWU's website.

Meanwhile, maritime organizations across the world responded to the threat saying they would refuse to receive any ships that were manned by the Army, per ILWU.

The Labor Management Relations Act of 1947, better known as the Taft–Hartley Act, attempted to restrict the power of labor unions in the US.

The law made the ILWU's hiring hall, a site where workers are given daily assignments, illegal. The ILWU has been using the practice since 1934. It allows longshore workers who have been accepted into the union to have the first choice on available roles, while part-time workers -- also known as casuals -- are given leftover positions.

26,965 ILWU workers boycotted a vote on the labor act from the National Labor Relations Board (NLRB), ILWU said. Employers also attempted to have union leaders sign affidavits affirming they were not members of the Communist Party.

The union negotiated with employers for 95 days before a contract was reached that allowed them to keep the hiring hall and raise wages, the ILWU's website said.

The technology at the ports in the West Coast have come a long way since the early days. Today, the ports in Southern California have some of the largest robots in the world.

In the 1950s and 1960s, employers started to bring more technology to the locations.

"New ideas for cargo handling, revolutionary ship design, the introduction of strapped loads, large-scale use of containers, and numerous other devices would sooner or later bypass the existing rules," the ILWU said on its website. "Proposed legislation would also outlaw many of the guarantees and safeguards afforded by the old contract, leaving the workers with no new forms of security or protection in exchange."

In its 1960 contract, the union agreed to allow the employers to use "labor-saving devices" in exchange for several stipulations: the current workforce could not be terminated, but could be cut down through retirement which would include significant pension benefits, profits increases would be shared with workers, and machines would be used to address "hazardous work," per the ILWU's website.

It was the longest strike in the union's history.

The introduction of shipping containers, which were standardized in 1968, meant fewer workers were needed to unload containers. Gone were the days of "break bulk" unloading, when goods were stowed on ships in individual barrels and packaging.

The Mechanization and Modernization contracts (M&M) which were signed for five-year periods in 1960 and 1966 created a series of layoffs and took the power away from the unions, the ILWU said.

The strike allowed the union to secure a pay increase and additional medical benefits.

At the time, a work stoppage had the potential to cost the US about $1 billion per day in lost trade, according to CNN.

The ILWU called the PMA's claims of a slowdown "false" and said it was a tactic to get the Bush Administration to intervene, CNN reported.

Contract negotiations were at a stalemate as the ILWU refused to allow the PMA to institute new technology that could make clerks irrelevant.

After an 11-day lockout which left ships waiting for days outside of ports, Bush sought a court order to end the lockout that threatened to damage the economy when it was still reeling from 9/11.

"The crisis in our Western ports is hurting the economy," Bush said at a press event. "It is hurting the security of our country, and the federal government must act. Americans are working hard every day to bring our economy back from recession. This nation simply cannot afford to have hundreds of billions of dollars a year in potential manufacturing and agricultural trade sitting idle."

Under the Tart-Hartley Act, Bush sought an injunction against strikes and lockout that "imperil the national health or safety." It was the first time the act was successfully used since President Richard Nixon used it against the union in 1971.

The two groups reached an agreement about two months later. ILWU allowed the PMA to institute the new cargo-tracking technology while winning higher pay and pensions, Freight Waves reported.

Employers in 29 ports locked the longshoremen out, leading to dozens of ships idling off the coast.

The ILWU denied the allegations. The disruption cost the US billions of dollars and did not cease until the Obama Administration intervened.

The contract was extended in 2017 to be negotiated again in 2022.

The ILWU's history of strikes, from major demonstrations like that of 1971 or 1936 to smaller local strikes and political activism, has shown the union to be one of the most powerful in the nation.

Patrick Penfield, a supply chain management specialist at Syracuse University, told Yahoo Finance on Wednesday that the union likely will be in the "driver's seat" of negotiations.

The ILWU did not respond to a request for comment from Insider.

Any future slowdowns, strikes, or lockouts could mean further chaos for the US supply-chain which already has helped spur rampant inflation and shortages.