(CNN) Sen. Elizabeth Warren on Thursday unveiled her plan to overhaul the nation's immigration system, pledging to reverse a series of Trump administration policies and authorize her Justice Department to review allegations of abuse against detained migrants.

The proposal would decriminalize crossing the border into the United States without authorization and separate law enforcement from immigration enforcement, a plan first proposed by fellow 2020 candidate Julián Castro that Warren endorsed. Warren writes in her summary of the plan that, if elected, she would first seek to pursue her agenda through legislation, but "move forward with executive action if Congress refuses to act."

The Massachusetts senator rolled out her plan in a Medium post hours before addressing LULAC, a Latino civil rights organization, in Milwaukee, Wisconsin, and weeks after a public visit to a detention facility in Homestead, Florida, that is holding unaccompanied migrant children. She met there with local activists protesting the facility, waved to children from atop a stepstool that gave her a distant view inside, and denounced the practice of contracting out detention centers.

The crisis at the border has attracted national attention and unanimous condemnation of leading 2020 Democratic presidential contenders, nearly all of whom visited Homestead before and after the first round of primary debates. Warren had previously unveiled a plan to ban private prisons and detention facilities , should she be elected president in 2020.

In response to a swirl of recent reports alleging overcrowding and squalid conditions at similar facilities, Warren is pledging to hold the current administration accountable, saying she will "designate a Justice Department task force to investigate accusations of serious violations -- including medical neglect and physical and sexual assaults of detained immigrants." It would be granted "independent authority to pursue any substantiated criminal allegations."

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