The White House said Saturday that Republicans have “struggled to articulate a reason” to oppose President Biden’s $2.25 trillion infrastructure plan.

In a White House memo obtained by The Hill, adviser Anita Dunn touted growing momentum for Biden’s proposal, citing positive reports from bond credit rating company Moody's, and growing support from climate experts, economists and others. 

Republicans, however, have criticized the proposal’s price tag, arguing that it advances progressive agenda priorities unrelated to infrastructure.

Senate Majority Leader Mitch McConnell (Ky.), said on Wednesday that “the latest liberal wish-list the White House has decided to label 'infrastructure' is a major missed opportunity by this Administration.”

Other members of the GOP have railed against Biden's plan to spend billions on electric vehicles, a corporate tax increase and other measures to combat climate change that are included in the proposal. 

In Saturday's memo, Dunn said that Republicans have struggled to articulate a reason to oppose a plan that has support from the public. 

“In the face of massive support from the public, it’s no surprise that Republicans have struggled to articulate a reason to oppose the President’s plan. And in trying to attack the President’s proposal, Republicans have had to run away from their own record of supporting critical investments in our infrastructure,” Dunn wrote.

“And while President Biden plans to more than pay for this plan by asking big corporations to pay their fair share, Republican lawmakers have been quick to come to the defense of multinational companies,” Dunn continued.

Biden unveiled the plan in Pittsburgh on Wednesday, which aims to repair 20,000 miles of road, 10,000 bridges, expand broadband access to rural and underserved communities, replace the nation’s lead and service pipelines to ensure clean water, invest in research and development and manufacturing and expand access to home and community-based care.

The president proposes to fund the plan over 15 years by raising the corporate tax rate from 21 percent to 28 percent.

Dunn noted that in a recent poll conducted by Morning Consult and Politico, 1 in 2 voters said they approved of an infrastructure plan funded by raising taxes on wealthy Americans and corporations.  

But amid zero support from the GOP and a 50-50 Senate, it is likely that Democrats will have to push the legislation through Congress through budget reconciliation, a process which allows the Senate to bypass the 60-vote filibuster. 

The Biden administration announced this week that it hopes the plan will be passed by the summer. 

Morgan Chalfant contributed to this report