California’s Fair Political Practices Commission, the state’s political ethics watchdog, made a small but significant change to its lobbying rules last week. It adopted a rule that requires trade groups, corporations, unions and other special interests that hire lobbyists to separate and publicly itemize their expenses in the “other payments to influence” category in their required quarterly state reports.

The change sounds technical, and it is. But the commission’s action closes an important loophole that should have ended decades ago.

Under the previous rules, the “other payments to influence” category allowed these groups to combine large sums spent on lobbying efforts into a single general category — denying the public information about payees, goods or services paid for, and the amount paid.

It’s a loophole that can include expenditures that are crucial to influencing public officials — like grassroots advocacy campaigns, advertising and hiring consultants.

As Consumer Watchdog wrote in a letter in support of the rule change, “While (lobbying groups) must disclose if they spent money buying a lawmaker a coffee, they can hide the fact that they spent millions on advertising campaigns as other payments without giving details.”

The chance to spend freely under the radar didn’t go unnoticed by these groups. The “other payments” category has greatly expanded over the past several election cycles. Lobbyist employers spent 52 percent of their total reported payments on this “other” category in 2000, and 69 percent in 2014.

Of the 10 interest groups that spent the most on lobbying in 2014, many of them reported an even higher percentage of “other payments to influence” spending (Western States Petroleum Association spent 81 percent, for example, and the California State Council of Service Employees spent 79 percent).

“Over the last six to eight years we’ve seen a big increase in this category,” said FPPC communications director Jay Wierenga. “With almost 70 percent of lobbying only called ‘other payments,’ we felt like the public deserved to know more about what that money was being spent on.”

That’s for sure.

With the 2016 election coming up, the rule change is happening not a moment too soon.

If anything, this change should have happened sooner.

Asked why the commission didn’t take action, say, in 2000 when 52 percent of total payments were being described as “other,” Wierenga said, “There’s been resistance at some base level from the lobbying industry. And I think that previous (commission) chairs had other, higher priorities.”

“Resistance” from the lobbying industry suggests that the commission must be watchful about how the new rules are applied.

Already, Consumer Watchdog has alerted the commission that allowing an option to disclose payments as “public affairs” could allow lobbyist groups to hire third parties to avoid disclosure. It may sound cumbersome, but lobbying groups are dogged in their quest for influence. That’s had negative effects on the public’s interest, and it's always a potential threat.