President Obama’s campaign is up with a new ad contrasting his tax plan with Mitt Romney’s and accusing Romney of wanting to raise taxes on 18 million Americans.

The ad accuses Romney of supporting tax breaks for the wealthy, for oil companies and for those who ship jobs overseas, along with a tax increase for 18 million “working families.”

The ad represents the Obama campaign’s decision to double down on its message of raising taxes on the wealthy by letting the Bush tax cuts expire. But it also shows a desire to open up a new front by attacking Romney as a potential tax-raiser too.