When I worked at a newsmagazine and the editors needed a headline for the cover after some major event, we often hauled out a hardy perennial:

“Now for the Hard Part.”

President Barack Obama, almost marginalized in Washington this summer by a crafty opposition, is back in the game with a vigorous, sensible and, above all, muscular speech that led from the front instead of the rear. Overnight, the conventional wisdom in Washington went from “nothing will pass” to “they’ll salvage something from this.”

The question is whether that something is sufficiently potent to forestall a recession and nudge unemployment lower next year. Republicans would like to do just enough to stop Obama from reviving Harry Truman’s “Do Nothing Congress” epithet without the economy improving enough to secure his re-election.

(If you find that too cynical, how else do you explain their insistence all year on a total focus on deficit reduction, which does nothing in the short term to put people to work?)

To win passage of the full American Jobs Act, Obama needs to follow up with an autumn offensive worthy of another of his Democratic predecessors. Recall the iconic photos of Lyndon B. Johnson towering over diminutive Rhode Island Senator Theodore Green, his hot breath in Green’s face. Pundits of the period called it “The Treatment.”

Obama is temperamentally incapable of “The Treatment,” but he has a weapon that LBJ lacked: a bad economy. The flip side of 9 percent unemployment is that it puts pressure on members of Congress to support desperately needed jobs in their districts.

With more than $245 billion in tax cuts, some version of the Obama bill has a decent shot of clearing the Senate. The problem will almost certainly be in the House of Representatives, where both parties may have trouble getting their bases to accept the bill, especially after Sept. 19, when the president specifies how he would pay for it.

House Minority Leader Nancy Pelosi told me in June that she is adamantly opposed to any changes to Medicare, which Obama said in his speech must be reformed. She and many other Democrats don’t want to muddy their attacks on the Republican Party over what they see as politically suicidal support for Rick Perry-style gutting of entitlements. The president will have to convince these Democrats that he’s not paying for corporate tax cuts with Medicare benefits.

On the other side, the Tea Party will obviously put enormous pressure on the Republican House leadership to strip out investment in infrastructure (a word Obama blessedly avoided in his speech), youth employment programs and anything else that smacks of “spending.”

To win enough votes for passage, Obama’s Isaiah approach (“Come now, let us reason together”) needs a touch of Jeremiah (“A hammer that shatters a rock”).

The hammer approach should follow a new Obama dictum that goes like this: “If you say you don’t want it, you won’t get it.”

In other words, you vote for the jobs bill or no workmen will be fixing any roads, bridges or schools in your district. That’s the message Obama should deliver in the next week as he stumps for the bill in Ohio and Virginia, which are, not coincidentally, home to House Speaker John Boehner and House Majority Leader Eric Cantor.

The president needs to make clear that there will be no repeat of 2009, when some 70 Republican members of Congress issued press releases and otherwise took credit for the arrival in their districts of stimulus money they had all voted against.

Before you assume this kind of hypocrisy can’t be prevented, look at the design of the infrastructure bank that’s in the bill. The president said before Congress that the two criteria for deciding what the bank will fund are, “how badly a construction project is needed and how much good it would do for the economy.”

Now who do you think has to sign off on how badly a certain project is needed? To keep the projects clean and free of earmark-style influence, they will no doubt have to be designated as high priority by the American Society of Civil Engineers and other experts. But these projects are slated to be public-private partnerships, which means that buy-in will be necessary both from local investors -- who will trumpet how much good their projects would do for the local economy -- and from politicians.

Call it the velvet-covered fist. With the U.S. Chamber of Commerce and AFL-CIO on board, Obama can say to the local Republican congressman: “I’ve got two out of three of the main players -- business and labor -- but will not authorize the project in your district unless I have your political support for the whole jobs bill. If you want to vote against the bill -- if you want to stand in the way of your local business community’s backing of that new turnpike interchange -- that’s fine. We’ll build it elsewhere.”

More than likely, they’ll come around. Especially if they hear from their constituents. The hard part will be a lot easier if the American people tell our elected representatives what we tell pollsters in overwhelming numbers: that we want jobs, and we want them now.

(Jonathan Alter, a Bloomberg View columnist, is the author of “The Promise: President Obama, Year One.” The opinions expressed are his own.)

To contact the author of this column: Jonathan Alter at alterjonathan@gmail.com.

To contact the editor responsible for this column: Timothy Lavin at tlavin1@bloomberg.net.