Washington ? As Americans struggle with double-digit increases in their health insurance bills, millions are coming up against a hard reality: The state regulators who are supposed to protect them can often do little to control what insurers are charging.

In many states, it is the insurance industry that largely controls the regulatory process, funneling money to key state lawmakers and squelching efforts to expand government oversight of premiums, a review of state regulations and campaign donations shows.

“The pressure that the industry can bring to bear in state legislatures is unbelievable,” said J. Robert Hunter, a former insurance commissioner in Texas.

“They pretty much get what they want.”

Although the Obama administration’s health care overhaul is designed to ultimately change that, many consumer advocates fear the new law may not break insurers’ stranglehold on state capitals soon enough.

“A lot of us are scrambling right now to match the insurance industry’s influence,” said Larry C. McNeely II, health care advocate at the U.S. Public Interest Research Group, whose state offices are squaring off against insurers nationwide.

Since 2003, insurance companies and health maintenance organizations have given more than $42 million in state-level campaign contributions, often targeting lawmakers who sit on the committees that decide how much power regulators will have, according to campaign finance data analyzed by the Tribune Washington Bureau and the National Institute on Money in State Politics.

In some of the largest states, those same lawmakers have in effect blocked legislative efforts to control the industry.

Consumer advocates and administration officials are trying to spark new state efforts because the new health care law gives the federal government only limited power to regulate premiums, traditionally a state responsibility. The Obama administration plans to announce a series of $1 million grants this week to help states increase their oversight.

“The battle has shifted to the states,” said Washington state Insurance Commissioner Mike Kreidler, who is working to retain his authority to review insurance premiums.

Insurance industry officials say added regulation is unnecessary. America’s Health Insurance Plans President Karen Ignagni, who heads the industry’s Washington-based lobbying arm, said many insurance companies fear that elected officials will simply exploit new authority.

“They are worried about the politicization of the process. They are worried about not being able to get rates approved,” said Ignagni, noting that the new health care law includes other provisions to protect consumers, such as new rules requiring insurers to explain “unreasonable” rate increases.

Many Democrats and consumer advocates believe the provisions are inadequate. They want to give state regulators what is called prior-approval authority, which allows states to block rate hikes they deem unjustified.

That has been a powerful tool in states that have such power.

In Oregon, for example, officials have denied or modified 20 of 71 proposed hikes in the individual and small-group markets since April of last year.

Regence BlueCross BlueShield of Oregon was forced to cut back a proposed 26.4 percent increase in one of its individual plans to 17.3 percent. Other carriers were ordered to scrap altogether hikes as high as 20 percent.

But just 19 states have complete authority to do this in both the individual and small-group markets, according to a survey of state insurance regulators by the Tribune Washington Bureau.

And though some other states can review premiums in limited circumstances, most have minimal legal authority to challenge rate hikes before they show up in consumers’ bills.

Consumer groups and regulators have made some progress.

Washington, Colorado and Delaware have recently passed laws to give insurance regulators prior-approval authority. New York this year restored that authority after insurers successfully weakened state regulation in the 1990s.