He praised the audience of "job creators" and framed Warren's comments on government helping businesses as evidence of more than just flawed policy. Rather, he said, it's a flawed philosophy.

"To downplay individual initiative as nothing more than a byproduct of big government is to fundamentally misunderstand our free-enterprise system, and it is a backward view of who we are as Americans," he said, according to prepared remarks. He went on to argue that such a philosophy justifies out-of-control government growth.

Brown also slammed Warren as being pro-tax-increase.

"[E]ven Taxmageddon is not a big enough tax hike for professor Warren," he said, citing her support for various increases, including "a total of $3.4 trillion in higher taxes over the next decade, including $2.7 trillion in brand new tax hikes."

In contrast, he painted himself as a bipartisan reformer, an argument he'll have to win to take staunchly blue Massachusetts again this year. The most recent polls show Brown and Warren running neck and neck in the race.

The few tax policy details he offered — getting rid of loopholes, simplifying the tax code and lowering rates — were largely bipartisan, except for his support of a balanced-budget amendment to the Constitution, a proposal widely endorsed by conservatives.

In response, Warren issued a statement highlighting what she characterized as her differing priorities from those touted by Brown and attempted to tie the Republican to newly-minted vice presidential pick Rep. Paul RyanPaul Davis RyanRepublicans are avoiding gun talks as election looms The Hill's 12:30 Report Flake to try to force vote on DACA stopgap plan MORE (R-Wis.), a strategy Democrats hope will taint Brown with Ryan's clear conservative credentials.

"He can’t run away from his record, his endorsement of Mitt Romney and Paul Ryan or his Republican Party. They stand together to help the rich and powerful get richer and more powerful," she said.