evidence: FACT CHECK: Viral Post Falsely Claims Mitt Romney Has Threatened To Leave The Republican Party A post shared on Twitter claims Utah Republican Sen. Mitt Romney has purportedly threatened to leave the Republican Party and join the Democrats. [...] "Senator #MittRomney Threatens to Leave Republican Party and Join Democrats," the Twitter post, which includes a photo of the Republican Utah Senator and has been viewed over one million times, purports. The post does not provide a source to support the claim.