Estrada’s letter resonated among Republicans because to many in the GOP, he is the living symbol of a conservative judicial nominee mistreated by Senate Democrats. Smart, credentialed, with a fine record and impressive personal story, he was nominated by George W. Bush for a seat on the U.S. Court of Appeals in May 2001. Democrats blocked his nomination and ultimately resorted to a filibuster against him in 2003. In September of that year, Estrada withdrew his nomination. (Despite their friendship, Kagan, then a law professor at Harvard, didn’t write a letter on Estrada’s behalf.)

Today, the conservative expressions of support for Kagan have disappointed a number of Republicans who want a shootout over the nomination. They fully expect Democrats to cite that support (“Even Ken Starr says …”) over and over again during Kagan’s confirmation hearings.

But the bigger problem conservatives see is that the pro-Kagan statements put Republicans at a disadvantage before the confirmation even begins. “What Miguel and Ken are trying to demonstrate is that the president deserves to have his nominees confirmed as long as they are qualified,” says one GOP Senate aide. “The problem is the Democrats don’t do that, and so you unilaterally disarm.”