Sen. Tom Cotton, R-Ark., chided Sen. Lindsey Graham, R-S.C., on Thursday for accusing Stephen Miller, a White House senior policy adviser, of hindering efforts to reach a compromise on an immigration deal, and said it's beneath a senator to attack a White House aide.

“Embarrassing for a senator to attack a staffer,” Cotton tweeted. “No worse example of punching down & bullying someone who can’t defend himself.”

Embarrassing for a senator to attack a staffer. No worse example of punching down & bullying someone who can't defend himself. — Tom Cotton (@TomCottonAR) February 15, 2018



Graham criticized both Miller and a Department of Homeland Security press secretary as "two of the most extreme characters" in Washington dealing with immigration. The DHS press secretary, Tyler Houlton, used to work for Rep. Tom Tancredo, R-Colo., a longtime advocate of a fence along the U.S.-Mexico border.

Graham brought up Houlton as he was criticizing a statement from the Department of Homeland Security opposing a bipartisan immigration plan from the so-called “Common Sense Coalition.” The statement characterized the bipartisan proposal as an “egregious violation” of President Trump’s immigration framework, and said it would deprioritize the enforcement of U.S. immigration laws against all illegal immigrants who are in the U.S. today.

“The changes proposed by Senators Schumer-Rounds-Collins would effectively make the United States a sanctuary nation where ignoring the rule of law is encouraged,” DHS said.

Graham said Trump is “most days pretty good” on immigration, but warned he is “being led down a path where we won’t get a result.”

The proposal, which hasn’t yet been introduced, creates a pathway to citizenship for 1.8 million immigrants brought to the U.S. illegally as children and appropriates $25 billion for border security measures, including the border wall. But it also says the government should only prioritize illegal immigrants for deportation if they enter the country in 2018 or later.

The White House said Thursday the president would veto the bipartisan deal.

Anna Giaritelli contributed to this report.