Elizabeth Warren, a Democrat, is the senior senator from Massachusetts. The views expressed are her own.

(CNN) Over the past eight years, President Barack Obama has advanced strong executive actions and federal rules that have provided millions of people with better wages, better benefits and stronger protections in the workplace. On Friday, a new president will move into the Oval Office. He will face a stark choice -- expand on those efforts or destroy them.

Faced with this dereliction of duty, Obama and his Labor Department have done what they can for workers. It hasn't been enough to shore up a crumbling middle class, but it's been a lot.

They acted to improve wages. By expanding overtime pay to more than 4 million Americans, the new labor rules would put as much as $1.3 billion a year in the pockets of workers. They bumped up the minimum wage for federal contractors to $10.10 an hour, providing an estimated 200,000 low-wage workers with a raise.

They required government contractors to provide workers with up to seven paid sick days per year, which increased this emergency time-off option for more than 1 million workers. They prohibited federal contractors from denying jobs to otherwise qualified workers based on gender identity or sexual orientation and expanded equality in the workplace. They even finalized a long-delayed rule to protect workers exposed to silica dust from contracting horrible diseases such as silicosis, lung disease and cancer. These and other actions over the last several years have made a big difference to families across this country.

Every one of these rules could have been passed by Congress, but because Republicans refused to help, they were accomplished instead by rule making and executive orders. This left industry advocates free to challenge the new provisions in court.

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Today, many of these initiatives are in jeopardy. A federal judge in Texas recently issued a decision at least temporarily blocking new overtime pay requirements for millions of workers -- a legal fight that will drag into the new administration. In fact, every single one of these requirements to help workers could be reversed by the new President.

Paid sick days, a higher minimum wage and discrimination-free hiring for federal contractor employees? Gone. Protections from dying of dangerous silica exposure on the job? Out the window. Getting paid for overtime for the hours you actually work? Promises turned to dust.

Donald Trump doesn't need to reverse these gains. After all, he won the presidency while arguing that he would stand up for workers and promising millions of "high-paying jobs" for working-class Americans. But now he's pulling a fast reversal. The President-elect has already promised to "cancel immediately," "eliminate" or "repeal" Obama's executive orders and agency regulations. If he follows through on that promise, many of these worker benefits will be obliterated.

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The political campaign is over, and Trump is poised to assume the presidency. When it comes to the economic futures of millions of working families, the stakes could not be higher. Americans will judge the President-elect not by his past promises but by his future actions.

There are Americans busting their tails working full-time jobs and still living in poverty, Americans who log massive hours and depend on overtime payments to put food on the table, Americans who can't take a day off to care for a sick child without getting fired, Americans who've been denied good jobs because of who they are or who they love, Americans who've watched co-workers die horrific deaths from silica exposure.

Now it's time for Donald Trump to show his true colors. Will he stand with working people? Or will he toss them overboard and cozy up with corporate CEOs and congressional Republicans who are peddling the same tired old anti-worker plans?