While union membership has been much higher historically than it is right now, labor organizing has never been more popular with the American public, and business owners are collectively paying $340 million each year to put a stop to it.

For Americans reading the news, it may be unclear why companies are willing to pay so much to fight collective bargaining. Businesses are willing to shell out millions of dollars to fight union efforts instead of putting that money towards addressing the issues that often inspire labor movements in the first place.

Also, despite the massive amounts of cash put behind anti-union efforts, they aren't always successful. Last year, Amazon (AMZN  ) spent roughly $4.3 million to fight organizing efforts at company warehouses. Despite that investment, a Staten Island warehouse successfully became the first Amazon facility ever to unionize.

According to Marketplace, unions help to improve the lives of workers across the economy, not just union members. Collective bargaining gives workers access to higher wages, better benefits, and improved working conditions.

Despite this positive impact, employers continue to fight organization efforts. Beyond the potential additional cost in wages, labor experts say that many businesses fight against unionizing for ideological reasons. Employers simply don't want to relinquish any control of their workers.

"American employment law is very pro-employer. There are obviously some exceptions, but there's a lot you can do without worrying about anything," Jeffrey Hirsch, a law professor at the University of North Carolina, told Marketplace. "That changes pretty dramatically when a union comes in. In particular, you can't make changes to the terms and conditions of work without bargaining with the union."

Even though there are some claims that unionizing improves worker performance thus offsetting costs, many business owners will continue to fight to keep ahold of their power.

"They think, 'I created my company because I'm a special genius. We live in a meritocracy. My success proves I know more, I'm better at this than other people,'" Joshua Freeman, a history professor at the City University of New York's School of Labor and Urban Studies, told Marketplace.

Consultants are sometimes paid more than $350 per hour to help big corporations fight unionizing campaigns. Consultants help businesses train managers to discourage unionization, give anti-union company presentations, and use other tactics to stop labor movements.

"You're hiring attorneys who specialize in this work, giving advice to companies about what they can do, what they can't do," Hirsch said. "Or, to be perfectly blunt, sometimes I think even what you can't do - but you might want to do anyway."

In fact, illegal or improper activity is rampant in corporate anti-union efforts. According to the Economic Policy Institute (EPI), 20% of all union votes result in employers being charged with labor law violations.

Labor experts say that most businesses follow the same basic tactics for fighting unions. One of the most common forms of anti-union activity is so-called captive-audience meetings.

These meetings are mandatory for employees and involve consultants and management trying to stop employees from voting in favor of unionizing. Employees often report that managers and consultants make untrue statements about the effects of unionizing, including that the workers will be fired if a union is formed.

"Sometimes these meetings can skirt the law with implied threats," Freeman told Marketplace.

However, businesses may not be able to get away with these meetings for much longer. While they are currently allowed during union campaigns, the National Labor Relations Board's (NLRB) general counsel is seeking to change that. NLRB general counsel Jennifer Abruzzo wrote in a memo that captive-audience meetings are "inconsistent" with labor law.

"This license to coerce is an anomaly in labor law, inconsistent with the Act's protection of employees' free choice. It is based on a fundamental misunderstanding of employers' speech rights," Abruzzo wrote. "I believe that the NLRB case precedent, which has tolerated such meetings, is at odds with fundamental labor-law principles, our statutory language, and our Congressional mandate. Because of this, I plan to urge the Board to reconsider such precedent and find mandatory meetings of this sort unlawful."