President Obama sounds like a man back on the offensive.

The president is reprising his core message that what the economy needs is more federal spending on popular priorities such as infrastructure and education, not less.

And his stump speeches last week in Illinois, Missouri and Florida put Republicans on notice that he will blame them if a standoff over spending results in a government shutdown or a financial crisis over the federal debt ceiling this fall.

“Repealing Obamacare and cutting spending is not an economic plan,” Obama lectured his opponents. “You can’t just be against something; you’ve got to be for something.”

But is that true?

House Speaker John A. Boehner, R-Ohio, doesn’t seem to think so. When asked recently about the glacial pace of legislation in the House, he responded: “We should not be judged on how many new laws we create. We ought to be judged on how many laws that we repeal.”

Boehner has a point. The number of bills a Congress passes is no guarantee that it’s doing important work. Roughly a third of the measures Congress passes are inconsequential actions such as renaming post offices.

But there’s also a flaw in Boehner’s argument. Although the current Congress is on pace to pass even fewer laws than the previous one (which set a modern record for lack of productivity), it hasn’t succeeded in repealing many laws either. The GOP-led House has voted nearly 40 times to repeal all or part of Obama’s health-care law, for example, but hasn’t succeeded in overturning the act — although it has cut its funding.

Boehner has said he has no intention of shutting down the government during budget talks this fall, a move he believes would be counterproductive.

As one of his allies, Rep. Tom Cole, R-Okla., put it last week: “The only way Republicans will lose the House is to shut down the government or default on the debt. Shutting down the government is not in the best interests of the American people, and it makes you look politically irresponsible.”

But Boehner doesn’t always control the majority of his own caucus. Tea party radicals in both chambers of Congress are demanding a hard line, with some, including Florida Sen. Marco Rubio, promising to block any increase in the federal debt ceiling unless Obama’s health-care law is repealed — a proposal another Republican, Sen. Richard M. Burr of North Carolina, called “the dumbest idea I ever heard.”

That’s no guarantee it won’t gain traction. Members of Congress in safely partisan districts — including some liberal Democrats as well as tea party conservatives — can be remarkably indifferent to broader public opinion. That’s one reason Congress’ approval rating dropped last week to an all-time low of 12 percent in the NBC News-Wall Street Journal Poll, far below Obama’s anemic rating of 45 percent.

It’s also well below the level Congress sank to last year, when Sen. John McCain, R-Ariz., joked that its only remaining supporters were “paid staff and blood relatives.”

Obama hasn’t given up hope that he can spur legislators to action. He’s trying to win legislative battles on both immigration and the budget by striking bipartisan compromises in the Senate, which still has a sizable faction of Republicans who say they want to negotiate with the president.

Even as he denounced House Republicans last week, Obama doled out elaborate praise for a few, unnamed Republican senators who he said were working toward bipartisan compromises.

“The Senate is their only hope,” said Norman J. Ornstein, a congressional scholar at the American Enterprise Institute. “If you begin to get 70 or 75 votes for things in the Senate, then you get a different conversation; it becomes clear that there’s only one group of people (the House conservatives) standing in the way.”

Obama is doing everything he can to cast the opposition as being obstructionist. But will his return to the campaign trail have any real effect on Congress?

The too-easy answer is no. He’s given speeches like these before. He’s got no new proposals to unveil. And the House members who stand in his way aren’t worried about pressure from voters who support the president; they are more worried about primary challenges from even more conservative Republicans to their right. Speeches from the president aren’t going to change their minds.

But that’s not what Obama’s campaign is about. On one level, it’s about influencing votes in the Senate, not the House. And on another, it’s about making sure that if this fall’s budget battles do result in a government shutdown or, even worse, a financial crisis over the debt ceiling, the president and his party don’t get blamed.

Obama may look and sound as if he’s on the offensive, but his strategy has an awful lot of defense in it too.

Doyle McManus is a columnist for the Los Angeles Times.