Senate battle heats up over 'blue slips,' Trump court picksThe Hill, Oct 11, 2017
The "blue-slip" rule — a senatorial courtesy upheld by tradition — allows a home-state senator to stop a lower-court nominee by refusing to return a sheet of paper, known as the blue slip, to the Judiciary Committee.
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But because the Senate's "blue slip" practice isn't a rule but a tradition enforced by the Judiciary Committee chairman, the decision on whether or not to move forward ultimately rests with Sen. Chuck Grassley (R-Iowa.).
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Sen. Patrick Leahy (D-Vt.), a former chairman of the committee, added that it was “not up to McConnell” and that Grassley had made him a promise on blue slips.
“Chairman Grassley has told me he will respect the blue slip tradition, just as I did. I trust him to keep his word,” he said on Wednesday.
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http://thehill.com/homenews/senate/354955-senators-battle-over-trumps-court-nominees