WASHINGTON – Sen. Robert Menendez, the chamber's most senior Hispanic member, warned Tuesday that Donald Trump is taking the country and the Republican party "down a dark and slippery slope," urging GOP lawmakers to speak out against their presumptive presidential nominee and comparing his rhetoric to that of tyrants.

"The road to some of the darkest moments in history have been paved with the rants of petty demagogues against ethnic minorities for centuries, and now again in this century Donald Trump is echoing those same racist rants, and by doing so threatening to take this nation to a dangerous place," Menendez, a New Jersey Democrat, said in a floor speech Tuesday morning.

He said racism is "page one on the dark chapters of history" as tyrants and dictators "separate us from them … in order to consolidate power for themselves."

Menendez said he had "thought long and hard about giving this speech" but felt he had to speak out in the wake of Trump's recent comments about a Hispanic-American judge.

Trump ignited a political firestorm by suggesting that U.S. District Judge Gonzalo Curiel may be biased by his Mexican heritage as he oversees a lawsuit against the defunct Trump University. Curiel was born in Indiana to parents who were immigrants from Mexico.

Many Republicans have condemned Trump's attack – House Speaker Paul Ryan on Tuesday called it "the textbook definition of a racist comment" – but Ryan, like others, continue to say they will support Trump as the GOP nominee.

The controversy is exactly the kind many Republicans worry will damage their party in key down-ballot campaigns, including the Pennsylvania Senate race and closely-contested House contests, such as the one underway in a Bucks County-based district.

Sen. Pat Toomey (R., Pa.), facing one of the country's toughest Senate races, called Trump's comments "outrageous, disturbing and absolutely ridiculous," according to The Guardian.

Menendez said Republicans have fostered the environment that led to Trump with their attacks on President Obama – "they have given quarter to snake oil salesmen and conspiracy theorists" – and he said GOP lawmakers need to go further in rejecting the nominee.

"They have not called him out as they should, politics aside, for the threat he poses to this nation if he is elected," he said.

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