WASHINGTON (AP) — Republican Sen. Josh Hawley is hitting back at GOP colleagues who are criticizing his attempt to overturn the presidential election won by Joe Biden.

In a lengthy email, the Missouri Republican defended his rationale for challenging President Donald Trump’s defeat. He and other Republicans are planning to mount objections to the results when Congress convenes for a joint session Wednesday to confirm the Electoral College tally.

Hawley specifically defended himself against criticism from GOP Sen. Pat Toomey of Pennsylvania as he challenges that state’s election results.

Hawley, a Trump ally and potential 2024 presidential candidate, insisted that constituents back home have been “loud and clear” that they believe Biden’s win over Trump was unfair.

“It is my responsibility as a senator to raise their concerns,” Hawley wrote late Saturday.

A growing number of Republican lawmakers are joining President Donald Trump’s extraordinary effort to overturn the election, pledging to reject the results when Congress meets next week to count the Electoral College votes and certify President-elect Joe Biden’s win.

Sen. Ted Cruz of Texas on Saturday announced a coalition of 11 senators and senators-elect who have been enlisted for Trump’s effort to subvert the will of American voters.

Trump’s refusal to accept his defeat is tearing the party apart as Republicans are forced to make consequential choices that will set the contours of the post-Trump era. Hawley and Cruz are both among potential 2024 presidential contenders.

Senate Majority Leader Mitch McConnell had urged his party not to try to overturn what nonpartisan election officials have concluded was a free and fair vote.

The 11 senators largely acknowledged Saturday they will not succeed in preventing Biden from being inaugurated on Jan. 20 after he won the Electoral College 306-232. But their challenges, and those from House Republicans, represent the most sweeping effort to undo a presidential election outcome since the Civil War.