So now we know. When the Legislature reconvenes next month for brief organizational sessions, it will have historic Democratic supermajorities – 54 Assembly members and 29 senators.

However, when it returns to Sacramento in January, supposedly to do its real work, those numbers will change, because two Democratic senators will resign to take their seats in Congress, and that will touch off a game of musical chairs.

Those two departing senators, Juan Vargas and Gloria Negrete-McLeod, will almost certainly be succeeded by Democrats, most likely members of the Assembly who then would have to resign, thus sparking special elections for their seats that would stretch over most, of not all, of the 2013 session.

By winning 29 Senate seats, Democrats could lose Vargas and Negrete-McLeod and still have a 27-senator supermajority, which means they could, in theory, move legislation – tax increases and constitutional amendments – without Republican votes.

But it's more theory than reality. There are at least four Democratic senators who would be very uncertain votes for major legislation that falls into the "very liberal" category, especially if it adversely affects business interests.

Lobbyists for the California Chamber of Commerce and other business groups will be paying a lot of attention to those four – Rod Wright, Ron Calderon, Lou Correa and Michael Rubio.

Nor would Cathleen Galgiani, the 29th Democrat elected this year, whose paper-thin victory was finally declared last week, be eager to vote for anything that might backfire later in her fairly conservative San Joaquin Valley district.

So while liberal activists may be clamoring for Democrats to act quickly and boldly on taxes, environmental regulations, curbs on initiatives and other matters, the Senate votes are probably not there.

The votes might be there when the two vacant Senate seats are filled, but if even one Democratic Assembly member moves up to the Senate, it would suspend the party's supermajority in that house until the vacancy is filled by another special election.

Meanwhile, Democratic Sen. Curren Price is almost certain to resign from the Senate by June to take a seat on the Los Angeles City Council, which would spark another special election. If it were to be won by a Democratic Assembly member, there would be still another Assembly vacancy.

Finally, even were two-thirds votes to be mustered in both houses for the bold steps that liberal activists want, they'd have to contend with Gov. Jerry Brown, who has reiterated his 2010 campaign pledge not to raise taxes without voter approval.

The supermajorities have sparked lots of radio talk show and blogosphere speculation about what could happen – but what actually does happen is likely to be much more modest.

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