The Senate this week, by a vote of 59-40, endorsed limiting the reach of a rule proposed by the Obama administration to redefine what ditches, ponds, and other features are regulated by the Clean Water Act.

Sponsored by Senator John Barrasso (R-WY), the vote on a non-binding amendment to the Senate budget resolution served as a test of support for blocking or rolling back a rule proposed a year ago by the Environmental Protection Agency to define what can be regulated under the law as “Waters of the United States” (WOTUS).

The budget resolution, which does not need to be signed by the president,  provides an opportunity for senators to offer amendments that will serve as test votes on a variety of issues. Barrasso said the amendment would make “crystal clear” what the law should not regulate.

The vote margin suggested there could be a filibuster-proof, 60-vote margin for a standalone WOTUS bill or amendment later.  Texas Republican Ted Cruz missed the vote and would have almost certainly provided the 60th vote. However, the vote on the measure was well short of the two-thirds margin that would be necessary to overcome a presidential veto.

The vote had some Democratic support. Five Democrats and Maine independent Angus King supported the amendment, which spelled out various features that should be exempt from the anti-pollution law including isolated ponds, roadside ditches, irrigation ditches, and stormwater systems. Most of the Democrats who voted for the Barrasso amendment, except Joe Manchin of West Virginia, represent major farm states, including Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, Amy Klobuchar of Minnesota and Claire McKaskill of Missouri.

Democratic support for the Barrasso amendment may have been more, except for a competing measure sponsored by the ranking member of the Senate Agriculture Committee Debbie Stabenow (D-MI). Her amendment, adopted 99-0, called for protecting existing exemptions for agricultural practices while relying on scientific standards for protecting water quality.

Senator John Hoeven (R-ND), who is cosponsored the amendment, said earlier that the vote could indicate whether there is enough support to kill the rule. Otherwise the only remedy will be to use the appropriations process to block enforcement of the rule for fiscal 2016, which starts October 1.

Don Parrish, an environmental policy specialist for the Farm Bureau, called the Barrasso amendment a “step in the right direction.” “All this does is clarify in a nonbinding budget resolution what EPA has already said they are not regulating,” Parrish said.