Normally, Democratic senators can be expected to stand with President Obama and his proposals, but some key lawmakers may become obstacles in the path of cap-and-trade carbon emissions standards.

Citing the burden the standards would put on manufacturing, particularly automobile-related manufacturing, Michigan Democratic senators Carl Levin and Debbie Stabenow are signaling their opposition.

Levin, six other Democrats and 26 Republicans are objecting to a Senate procedural budget reconciliation process that would limit debate and amendments to Obama’s proposed debate cap-and-trade legislation, according to the Detroit News.

As for Stabenow, she thinks it’s unfair for Obama to tie his 10-year, $150 billion effort to boost alternative energy technology, including auto research, to the cap-and-trade plan. Stabenow said the auto industry needs financing for energy research “right now.”

Energy Secretary Steven Chu has pledged to work with Congress on passage of Obama’s cap-and-trade system.

Some funding aspects of Obama’s budget proposal would come from auctions for carbon emissions permits.