Having spent a few decades in California and with at least three very major earthquakes under by belt (when buildings and freeways and stuff broke), I’m more interested in political than physical tremors today.

Most traumatically for Democrats, there are signs that President Obama has not hit bottom in the polls. In Gallup, he’s reached a new approval low (38 percent) and new disapproval high (54 percent). He is statistically tied even with GOP candidates who have considerable liabilities and who remain unknown to a chunk of voters. (“President Barack Obama is closely matched against each of four possible Republican opponents when registered voters are asked whom they would support if the 2012 presidential election were held today. Mitt Romney leads Obama by two percentage points, 48% to 46%, Rick Perry and Obama are tied at 47%, and Obama edges out Ron Paul and Michele Bachmann by two and four points, respectively.”) The right track/wrong track direction polling reflects the public’s sour mood. A GOP operative puts it this way: “Every day it becomes harder to see how President Obama is going to find the momentum necessary to turn around these awful numbers. The election is a referendum and the American people are making their verdict pretty clear.”

With this in mind, Republican angst about finding a favored candidate should be put in context. Republicans will eventually find their standard bearer, and by then, the candidate will have gained credibility and polish. If Mitt Romney, for example, is the nominee, how easy will it be to paint him as some wide-eyed extremist or incompetent? (If the worst that can be said about him is that he is excessively practical and cautious it’s going to be tough to “kill him,” as an Obama operative put it.) If Texas Gov. Rick Perry manages to chalk up win outside the South (which he’ll have to do to win the nomination), he will, presumably, have figured out how to temper his rhetoric and Texas swagger. Democrats may take comfort in the absence of certain candidates (e.g. Rep. Paul Ryan, former Gov. Mitch Daniels), but they should be careful not to underestimate practiced politicians who are not entirely newcomers to the national scene.

It is not surprising then, as Gerald Seib put it in the Wall Street Journal, that there is “a distinct sense of rising anxiety” among Democrats. That is fueled by a raft of numbers numbers — the unemployment rate, the so-called misery index, presidential approval polling and national confidence — that are heading in the wrong direction for the president. And while there is no superstar Republican on the scene, Democrats may be catching on to a political reality: 2012 will be a referendum on Obama.

In short, Republicans can’t be counted on to self-destruct. Republican candidates may improve with time, but so long as the economy is skidding Obama will have an increasingly difficult time making the case that he deserves a second term.