Lindsey Graham has publicly come out in support of it now:
Graham on Wednesday said Congress should vote on language boosting the size of the stimulus checks and Section 230 of the Communications Decency Act.
“I support President @realDonaldTrump’s demand to increase direct payments for long-suffering Americans to $2,000 per person. And I also support his call to end Section 230 Big Tech legal liability protection. Let’s vote,” he tweeted.
... but not the House GOP leadership, it seems.
House Minority Leader Kevin McCarthy told fellow Republicans Wednesday that House Speaker Nancy Pelosi’s attempt to pass a bill boosting stimulus payments for individuals to $2,000 will fail, according to a person who participated in a private call with GOP House members. [...]
GOP lawmakers had resisted larger stimulus checks in an effort to hold the total cost of the pandemic package below $1 trillion, citing concerns about a wider fiscal deficit.
As far as I can tell, the only legislators who had spoken in favor of the $2000 figure before were some Democrats like Sanders and Markey, back in September.
Also, the Senate passed the CAA bill with 92-6, so they could override a presidential veto with ease. I guess Trump is betting they won't dare to go against him (given his traction with the base) or something like that. Of some note here, Trump just vetoed the NDAA, setting up a real showdown with Congress on that. An unnamed Senate GOP aide was quoted by the Hill saying that "There are at least 19 Republicans that will override both vetoes".