Democrats and their allies kept up their criticism of presidential candidate Mitt Romney Wednesday despite Newt Gingrich's surge in the polls, the latest sign that they see Romney as the biggest threat in the general election.

The Democratic-affiliated labor group Americans United for Change released a new website, Web video and Twitter account comparing Romney to Gordon Gekko, the millionaire villain in the 1987 movie "Wall Street," while the Democratic National Committee put out a Web video attacking Romney for not releasing his tax returns or the names of top donors. The Democratic outside group American Bridge put out a video of Romney saying the health insurance overhaul he enacted as Massachusetts governor should be a model for the nation.

There has been very little criticism of Gingrich from these and other Democratic groups, who are holding their breath and hoping the former House Speaker becomes the nominee.