Democratic Sen. Elizabeth Warren formally launched her presidential campaign on Saturday at a rally in her home state of Massachusetts, marking the final step in a process that had been underway for months.

Warren made little secret for years of the fact that she was considering a White House bid, and the former Harvard Law School professor has been considered a top contender among Democrats ever since she was first elected to the Senate in 2012.

Warren's announcement Saturday in Lawrence, Mass., was the first event in a seven state tour of early voting primary states. After Lawrence, Warren's campaign said she planned to travel to Iowa, New Hampshire, South Carolina, Georgia, Nevada and California.

Even before Warren's formal announcement, President Donald Trump's reelection campaign sent out a statement lambasting the senator and her policy positions.

"We are here to take on a fight that will shape our lives, our children's lives and our grandchildren's lives, just as surely as the fight that began in these streets more than a century ago," Warren said, in a statement posted to blogging site Medium.

"Because the man in the White House is not the cause of what's broken, he's just the latest — and most extreme — symptom of what's gone wrong in America," she added.

So far, there has been little reliable polling on the 2020 Democratic presidential field, which is growing on a near daily basis. But there is some good news in the numbers for Warren. A recent Politico-Morning Consult poll showed that more than half of all Americans already support what is expected to be a pillar of Warren's candidacy: Higher taxes on the ultra-wealthy.

"This is the fight of our lives. The fight to build an America where dreams are possible, an America that works for everyone. I am in that fight all the way," Warren said on Saturday. "And that is why I stand here today: to declare that I am a candidate for President of the United States of America."

An Oklahoma native who moved to Massachusetts as an adult, Warren has already staked out the issues of economic equality and anti-corruption, well ahead of the rest of the Democrats expected to run in 2020.

Both are subjects that Warren is uniquely positioned to tackle, given her experience as both a professor and her legislative record as a senator.

This fall, Warren introduced sweeping new ethics legislation, no doubt with an eye toward her 2020 campaign platform. The Anti-Corruption and Public Integrity Act would place a lifetime lobbying ban on former presidents and vice presidents, Cabinet secretaries, members of Congress and federal judges. It would also require presidential candidates to release at least eight years of tax returns — President Donald Trump has refused to release any of his tax returns.

Also this fall, Warren introduced the Accountable Capitalism Act, which would require, among other provisions, that employees be given seats on the board of directors at some of the nation's biggest companies.