At the heart of an intraparty Republican dispute over the best way to derail Obamacare is a disagreement over strategy  but also a divergence of opinion regarding how Americans might view the law once it is fully implemented.

Until recently, Republicans unanimously agreed that the Affordable Care Act was a lemon that would be rejected by voters  so much so that they predicted that the ongoing implementation of the law, which is due to accelerate next year, could be a boon to GOP congressional candidates in the 2014 mid-term elections.

Republicans believed that the growing fury over Obamacare, as seen in public opinion polls, would provide them with the political strength required to make further dents in the law as a part of a multistep process that could eventually lead to repeal. Retaking the Senate in 2014, and bolstering their House majority, were seen as key components of the Republican Party's long game on Obamacare.

But now that strategy and assumptions about how Americans will receive President Obama's signature legislative achievement are being challenged  and not by the White House or congressional Democrats, but by a small band of influential conservative Republicans.

Backed by conservative activist groups, these members argue that moving to defund Obamacare in the spending bill required to keep the government running beyond Sept. 30, the conclusion of the fiscal year, is the GOP's "last chance" to block the implementation of the Affordable Care Act. These conservatives contend that Americans will never support repeal of Obamacare once they begin receiving taxpayer-financed health care subsidies.

This fresh divide among congressional Republicans was recently on full display.

On one side, Sen. Susan Collins, R-Maine, made the case for playing the long game. She said that voters will end up so disgusted with Obamacare after their insurance rates rise and they lose access to their current doctor  among other potential negative consequences  they will demand relief and turn to Republicans for help. Collins, a former Maine insurance official, is a moderate, but there's no daylight between her and conservative hardliners over Obamacare.

"There is growing opposition to Obamacare in this country; and I think that opposition will soar once it is fully implemented. And, to me that provides an opportunity to Republicans to replace the onerous and unworkable and unwise provisions of the law with better health care policy  and I think that should be our focus," Collins told reporters. "To lay down this gauntlet that we are not going to fund the government unless Obamacare is completely repealed is a totally unrealistic policy, when the Senate is controlled by the Democrats and President Obama is still in the White House and would veto the bill."

On the other side, Sen. Ted Cruz advocated the defund-or-shutdown strategy, warning that stopping Obamacare is a now-or-never proposition. The Tea Party-affiliated Texan is among the handful of Republicans driving this effort.

"The Obama administration's plan, I believe, is to get to Jan. 1; Jan. 1 is when the exchanges start and the subsidies start, and the administration's plan is to try to get as many Americans as possible addicted to the sugar  addicted to the subsidies," Cruz said. "In modern times, no major entitlement that has been implemented has ever been unwound. And, so in my view, if we do not stand on principle, now, it is likely that we never will repeal Obamacare."

"There is no good alternative," he said. "We either stand for principle now, or I believe we surrender to Obamacare permanently."