Although Senate Republicans had enough votes to begin considering bills to repeal the Affordable Care Act, Sen. Jeff Merkley is seeking to make it tougher for any legislation to pass.

He's planning to force Republicans to take up-or-down votes on whether veterans, pregnant women and people with specific health problems should face higher premiums or even lose insurance coverage through Medicaid.

Democrats are in the minority, so the most they can do is make it politically more difficult for Republicans to pass the legislation that is expected to strip health insurance coverage from millions of Americans.

Merkley has prepared 120 amendments to the bill being debated in the Senate now, and he plans to propose each of them during the so-called vote-a-rama, when senators are free to propose as many amendments as they want.

"The number of people who would be harmed by the dismantling of health care is so long that it would be impossible to list them all—but that doesn't mean we shouldn't try," Merkley said.

Merkley's amendments call for the Senate Committee on Finance to consider the impact of the proposed legislation on specific groups like veterans,  pregnant women and people with specific preexisting conditions. His amendments call for striking any provisions that are found to increase premiums or out-of-pocket costs for these groups, or that could eliminate Medicaid coverage for patients with one of twenty chronic illnesses.

"If the GOP is intent on ramming their destructive bill through, they should have to face head-on the disastrous effects it will have for America's veterans, children, cancer patients, and the peace of mind for every family across this country," Merkley added.

The vote-a-rama is a quirk of the Senate rules adopted by Tuesday's 51-50 vote to open debate on three Republican health care bills. The most-amended bill to ever go through a Senate vote-a-rama period had just 51 roll call votes, far fewer than what Merkley alone is proposing. The average reconciliation bill sees just 22 roll call votes.

The first of the Republicans' three health care bills failed to pass on Tuesday.