There’s a lot of nonsense on the presidential campaign trail right now, but if you look hard enough there’s also some real campaigning that might actually have an effect on the outcome of the presidential race.

For example: The emerging Democratic strategy is to find popular issues that Republican Members of Congress oppose, and to force votes on them. The goal: To try to make Mitt Romney choose between either appearing ideologically extreme or risking conflict within his own party.

Here’s why this strategy could work: Perceptions of ideological extremism are one of the few factors that influence voter perceptions of challengers, as George McGovern and Barry Goldwater discovered. So Romney presumably wants to move to the center on as many issues as possible, including the ones Democrats are pushing. And yet this isn’t easy, because Romney doesn’t want a civil war to break out in the GOP.

Dems are currently pushing votes on no less than three major issues, all of which are designed to force Romney to make difficult choices.

First up: The student loan rate extension. Romney has already committed to Barack Obama’s position on this one, but House Republicans are reluctant to go along.

Next: The Violence Against Women Act, where Republicans in Congress have objected to reauthorization if modest Democratic changes are included.

And after that, the Senate will be taking up the “Paycheck Fairness” bill, which covers discrimination against equal pay for women.

Each of these is apt to be highly popular, and yet in each case Congressional Republicans are expected to oppose the bills as proposed. A fourth possible vote, Chuck Shumer’s legislative push to undo the Arizona immigration law if it survives the Supreme Court, may be less generally popular, but might become a key issue for Latino voters.

In each case, the obvious general election position for Romney to take would be with the Democrats. If there were no cost, Romney would probably like to distance himself from unpopular Congressional Republicans. But there’s a lot of risk involved. Even with the nomination wrapped up, he still needs at least tacit support from major party factions. He certainly doesn’t want a convention disrupted by conservative demonstrations against the nominee.

That’s why the real players here are House and Senate Republicans, and more broadly, conservative opinion leaders. Of course Democrats are going to try to push Romney on these sorts of issues; of course he’s going to try to move to the center. But will conservative opinion leaders let him? Will Congressional Republicans (who have their own fears of being labeled RINOs) quietly allow Romney to break with them, or will conservatives punish him for pivoting away from their principles?

We don’t yet know the answer to these questions, and no single bill will matter all that much. But add it all up and these fights could definitely help determine whether Romney will be perceived as extremely conservative by November — which in turn could be decisive in dictating the outcome.