RALEIGH – Congressional and legislative elections held in non-presidential years are heavily influenced by turnout differentials. About 40 percent or more of the voting population is pretty reliably Democratic, a similar number is Republican, and one-fifth is undecided. In non-presidential years, a lot of the undecideds just don’t show, accentuating the importance of getting base voters to the polls.

In 1994, Republicans did a masterful job of maximizing their turnout, helped along by the infuriating start of President Bill Clinton. They made massive gains in both Congress and state legislatures. In 1998, the shoe was on the other foot. Democrats pushed turnout rates, particularly among the part of the party’s base that is found in black communities, to historic highs. They used tape-recorded messages from Clinton, Jesse Jackson, and others, focusing on hot-button issues such as hate-crimes legislation. The result was a strong Democratic showing in U.S. House races, defeat of several Republican Senate candidates (including incumbent Lauch Faircloth in North Carolina), and recovery in state legislatures (including the recapture of the North Carolina House).

So what happens this year? It’s hard to tell at this early date. Some indicators suggest that Republicans currently have the advantage. For example, a new survey by the Pew Research Center for the People and the Press found that Republicans are far more likely to express approval of their leadership in Washington than Democrats are in theirs (see here).

About 80 percent of Republicans approved of the performance of GOP leaders, while only 64 percent of Democrats expressed approval of their leaders. Also, barely half of Democrats (51 percent) said the party was doing an excellent or good job of standing up for such core principles as “representing the interests of working people, protecting minorities and helping the poor,” the Pew Center reports. By comparison, 61 percent of Republicans said their party was doing an excellent or good job of standing up for its core principles, such as reducing the size of government, cutting taxes, and promoting conservative values.

Of course, these numbers suggest that even among Republicans, a sizable number (39 percent) think their leaders aren’t standing up for core principles (I hear from these voters a lot, as they rip Washington Republicans for passing bloated farm bills, enacting protectionist tariffs, or shying away from market-based Social Security and Medicare reform). Moreover, the Pew poll joins several others in the field right now in not finding much of a partisan difference in generic congressional ballot questions, though arguably what matters more is the difference in enthusiasm between the two parties’ electoral bases.

Right now, it looks like Republicans might go into the fall campaign with a tailwind. Still, it’s not exactly a stiff breeze.