Story highlights While Republicans prepare for a vote on health care, they should keep an eye on the polls

At issue: Pre-existing conditions and the Affordable Care Act have polled well recently

Washington (CNN) House Republicans believe they have the votes to pass their attempt to repeal and replace Obamacare. But even if they manage to get the 216 votes they need, a slew of potential political pitfalls await.

Here's a look at six things that could go wrong -- even if the House passes the bill later Thursday.

1. The CBO score: In order to pass the bill with a simple majority, Senate Republicans need to wait until it is scored by the Congressional Budget Office -- which is a fancy way of saying they need to wait to find out how much it costs. When the CBO scored the first version of the American Health Care Act in March, it found that : In order to pass the bill with a simple majority, Senate Republicans need to wait until it is scored by the Congressional Budget Office -- which is a fancy way of saying they need to wait to find out how much it costs. When the CBO scored the first version of the American Health Care Act in March, it found that 24 million fewer people would have coverage by 2026 than under Obamacare -- although it would reduce the federal budget deficit by $337 billion over 10 years . It's not clear what the CBO will find -- in terms of the number of people covered or the cost of the overall legislation -- but that's sort of the problem. Would you buy a car if you didn't know how much it cost when you signed on the dotted line? (Related: I may have a car to sell you.)

2. The polling, Part 1: This is not a bill that the American people are clamoring for. In the : This is not a bill that the American people are clamoring for. In the most recent CNN/ORC poll in April , 47% approved of it while 48% disapproved. Meanwhile, Obamacare continues to grow more popular. In the latest Kaiser Family Foundation poll on the Affordable Care Act, 48% of people approved of it while 41% disapproved. That's a big change from where the bill spent much of the last several years -- with more people disapproving than approving.

3. The polling, Part 2: Not only is the public not exactly clamoring for the repeal/replacement of Obamacare but one of the key elements of the new House plan -- getting rid of the federal mandate that people with pre-existing conditions be covered -- takes aim at one of the most popular elements of the law. Large majorities of people -- even many whom express much less satisfaction with the overall ACA -- support the pre-existing conditions mandate. While Republicans will try to argue that putting $8 billion into "high-risk" pools will mitigate the problem of wiping out the pre-existing conditions mandate, that's a somewhat complex and convoluted argument to make.

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