As the Legislature adjourned for three months last Friday, the Capitol turned its attention to the Nov. 6 election, and particularly three – or perhaps four – state Senate contests whose outcomes could affect the balance of legislative power.

Democrats now hold 25 of the Senate's 40 seats. If they were to gain two more this year, they would have a two-thirds supermajority and could pass certain kinds of legislation, such as tax increases, without Republican votes.

That power would increase pressure on Republicans in the Assembly, who, it's assumed, will continue to hold more than a third of its seats and therefore could, if they hang together, block tax increases.

Such solidarity, however, is not guaranteed. This year, Assembly Speaker John A. Pérez was able to peel off enough Republicans to win Assembly approval of his measure that would raise taxes on some multistate corporations by more than $1 billion a year.

Back to the Senate.

The prospect of Democrats getting to 27 Senate seats this year arises from the new districts that an independent commission drew after the 2010 census.

It quickly became apparent that a two-seat Democratic gain in 2012 would be possible with those new districts. And when Sen. Tony Strickland, R-Moorpark, opted to run for Congress rather than run against Democratic Sen. Fran Pavley of Agoura Hills in a newly redrawn 27th Senate District, that two-seat gain appeared to be certain.

However, Pavley's record is somewhat to the left of the district's moderate political profile, so oddsmakers believe her Republican opponent – prosecutor and Marine Corps Reserve officer Todd Zink – has a fighting chance. Both parties and outside interest groups are pouring lots of money into the suburban Southern California district.

That said, to retain their leverage on taxes in the Senate, Republicans would not only have to defeat Pavley but win two other tight races in marginal districts.

Assemblyman Bill Berryhill, R-Ceres, would have to defeat Assemblywoman Cathleen Galgiani, D-Stockton, in the San Joaquin Valley's 5th Senate District. And Assemblyman Jeff Miller, R-Corona, would have to defeat Democrat Richard Roth, a local businessman and former Air Force general who was handpicked by Democratic leaders to win in Riverside County's 31st Senate District district.

The wild card in the Senate power struggle is San Diego County's 39th Senate District, where former Republican Assemblyman George Plescia has at least an outside chance of defeating Democratic Assemblyman Marty Block.

Can Republicans hold onto at least 14 Senate seats?

It's still an uphill struggle. But if they do, they have a fair chance of expanding their ranks by a seat or two in 2014, when another 20 Senate seats will be filled.

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