I’ve suspected for some time now that the California Senate race against Barbara Boxer was basically the high-watermark Senate race for the GOP – that is, the toughest race that has a non-trivial chance to be winnable if everything breaks just right. But the recent withdrawal of Evan Bayh from his own re-election race in Indiana (not as “safe” a seat as Boxer’s, given Indiana’s natural Republican tilt, but an entrenched incumbent with a $13 million warchest) is a reminder, as was Scott Brown’s victory in Massachusetts, that you really never know where your opportunities are until you press them.

The GOP in New York is already stretched fairly thin trying to fight a two-front war against what should be vulnerable candidates, Gov. David Paterson (who is basically doomed, but likely will be replaced as the Democratic nominee by the more formidable Attorney General Andrew Cuomo) and his Senate appointee, Kirsten Gillibrand (who should emerge successful from what nonetheless promises to be a vigorous challenge from former Tennessee Congressman Harold Ford). Former Long Island Congressman Rick Lazio is the leading contender to be Republican nominee in the Governor’s race, while the Senate field lacks even a candidate as mildly well-known as Lazio, assuming George Pataki resists entreaties to run.

Now, with polls showing the generally invulnerable-seeming Chuck Schumer bleeding popularity, Republicans may open a third front if they can talk longtime CNBC/National Review economics commentator Larry Kudlow into running.

Kudlow was previously mentioned as a possible Senate contender against Chris Dodd before the field lined up in Connecticut, but New Yorkers aren’t generally that picky about that sort of thing, at least in Senate races. Kudlow would lock up the Conservative Party nod, which always helps.

As the Daily News warns:

Schumer is a formidable opponent. While Wall Street might not be as happy with him as it once was, he still has managed to amass a whopping $19.3 million worth of campaign cash.

Also, the polls have been mixed on New Yorkers’ opinion of Schumer. A recent Q poll put his job approval rating at 58-30, while a Marist poll put him at just 47 percent – his lowest rating since April 2001.

Schumer is a relentless campaigner and, with the likely departure of Harry Reid, may end up running to be the leader of the Senate Democrats next spring. I can’t say I see a realistic path to beat him, from where we stand today, and Kudlow’s a political novice. That said, you gotta be in it to win it, as the saying goes; if something else comes out to drive Schumer down, you’d hate to not have a horse in the race. And even if Schumer does end up winning handily, if he’s forced to devote his time and money to running his own race instead of propping up Gillibrand and other Democrats around the country, Kudlow will have accomplished something.