As I noted, Harry Reid will unveil the merged Senate health care bill today at 3:15pm ET. This is pretty much on the expected schedule. Here are the key questions I’d like to see answered about the bill:

• The public option. Most reports say that Reid will include a national public option with a state opt-out in the bill. I would expect several amendments to be offered on the floor, to change the opt out to an opt in, or to add a trigger. Nancy Pelosi reacted favorably to the opt out over the weekend, though we don’t know the details yet, which I’d like to see answered by Sen. Reid. How will states be allowed to opt out? When? Will the opt out be tied to federal funding or shifts in the states to Medicaid?

UPDATE: Politico suggests that Reid doesn’t actually have all the votes for the opt out, and that he’s basically daring members of his own caucus to block it.

Leadership sources tell me that Reid, who spoke with virtually every member of his 60-member caucus this weekend, currently has between 56 and 57 votes for the opt-in, which is being pushed by Sen. Charles Schumer, according to Democratic aides.

A public option with a delayed “trigger” — supported by the White House and Maine Republican Sen. Olympia Snowe has between 58 and 59 backers. It could be floated as an alternative if the opt-out measure fails to obtain the 60 votes needed for cloture, sources said.

First, the story confuses the opt out with the opt in. Second, I find it hard to believe that the Majority Leader or the White House would risk a setback on cloture and the loss of momentum that would entail.

• Obama’s support and the trigger. The White House is furiously backpedaling on reports that they prefer the trigger to keep Olympia Snowe in the fold (I’m trying to confirm a report that Snowe would filibuster the bill as Reid will offer it, with a public option and an opt-out provision). The White House has on multiple occasions favored the trigger, whether for ideological or political reasons or just to get a bill passed. FDL Action has a petition to House progressives demanding no triggers for the public option, something about which very few House members have been favorably disposed. Jacob Hacker provided the wonkish case against the trigger over the weekend.

The White House will presumably offer a favorable comment after Reid unveils the bill, which Kremlinologists will surely pore over.

• The abortion question. This has basically been playing out in the House, where anti-abortion Democrats are threatening to hold up the bill if it “funds abortions,” and want to offer an amendment to strip that “funding” out. What these anti-abortion Dems call funding is the subsidies given to low-income people to buy public or private plans on the insurance exchange, some of which could offer reproductive health services in their plans, as 90% of all health plans currently do. In other words, the anti-abortion groups want to dictate to private insurance companies what they can and cannot offer to customers. It would be interesting to see what Reid, a pro-life Dem, would say to such a proposal, and what he offered in the bill he merged for the Senate.

• Immediate benefits. A story in today’s Politico quoted Debbie Stabenow and Chris Dodd pushing for some immediate benefits as a result of the bill. Most of the measures don’t go into effect until 2013, and Democrats don’t want to spend three years telling constituents they have to wait to see anything from the health care bill, as Republicans denounce it all the while. Among the provisions discussed are senior discounts on brand-name drugs, small business tax credits to purchase insurance, and a “high-risk pool” to help cover the uninsured who have been denied coverage for a pre-existing condition. Will any of these make the Senate bill?

• Anti-trust. While the House is reportedly planning to include a repeal of the insurance industry’s anti-trust exemption in their base bill, Reid has said he would allow an amendment to come to the floor with that language. Has he changed his mind and included it in the bill, thus negating the need to get 60 votes (which is likely to be required for all amendments)?

• Affordability. The Senate Finance Committee and the HELP Committee took sharply different paths to coverage subsidies for those who qualified for help purchasing insurance. Which version won out in the final bill?

• Mandates. Word has already leaked that the employer mandate will be shelved, with higher penalties for the “free rider” provision from the SFC. Speculation has been that the employer mandate may have been exchanged for the public option. Also at issue is the individual mandate to buy insurance. That was made weaker by the SFC, so one wonders if those provisions will remain.

…it should also be noted that this is the bill that hits the Senate floor. It is NOT the final bill. It would have to be merged with whatever passes the House, and the House bill is likely to be far more progressive, necessitating another round of compromises.