Speaker of the House John Boehner (R-Ohio), seen here on May 16, 2013, said Thursday, June 6, that President Obama is threatening a government shutdown. (Chip Somodevilla/Getty Images)

The White House and congressional Republicans traded shots Thursday over the possibility of a government shutdown as each side began positioning itself for a budget showdown in the fall.

Funding for the government is secure for nearly four more months, a relatively long time, given the recent history of deadline-pressure budget deals, but House Speaker John A. Boehner (R-Ohio) accused President Obama on Thursday of threatening a government shutdown by saying he will veto all of annual spending bills unless a broad budget plan is approved.

In a letter to Obama, the speaker said that those two issues should continue on separate tracks so that as House Republicans and Senate Democrats continue their long-shot attempt at a major budget accord, the government could remain open without the threat of even a partial shutdown.

“When such delicate discussions are underway, the introduction by your administration of such an explosive new dynamic . . . needlessly injects a new element of uncertainty into our economy and further jeopardizes hope for a bipartisan agreement,” Boehner wrote in remarks that he echoed in his weekly Thursday news conference.

Obama’s advisers dismissed the idea that his vow to veto spending bills is tantamount to threatening a government shutdown, instead insisting that the veto comment was meant to set up their argument that the spending plans advancing in the House would gut key domestic programs.

“The administration made one thing very clear this week: We simply won’t sign into law the Republican budget, which would drastically slash the investments the middle class, seniors and our economic growth depend on. The President’s policies, including signing into law over $2.5 trillion of deficit reduction, have contributed to the most rapid decline in the deficit since World War II,” Amy Brundage, a spokeswoman for Obama, said Thursday in a statement issued after Boehner’s news briefing.

The White House budget office issued the blanket veto threat late Monday in response to two spending bills that cleared the House this week. One would fund veterans affairs and military construction, while the other would fund the Department of Homeland Security.

Both adhered to spending levels approved in a blueprint drafted by House Budget Committee Chairman Paul Ryan (R-Wis.) that calls for the automatic spending cuts known as the sequester to remain in place through the coming fiscal year.

Both Democrats and Republicans are privately acknowledging that the overall sequester-level cuts are likely to remain in place for years, but the fights are going to be about how to slice up increasingly scarce funding for the agencies, with Republicans favoring the Pentagon and other national security priorities. The Ryan budget would shift the burden of those cuts away from veterans and national defense programs, and force domestic agencies to shoulder all of them.

Democrats oppose that approach and have called for much of the sequester to be canceled and replaced by higher taxes and other savings. But Republicans have declined to open formal negotiations to address broader questions, and the House has begun drafting 2014 spending bills as though its budget were in force.

The White House’s veto threat Monday represented its first real shot in the debate, following weeks of Democratic angst on Capitol Hill about the administration not drawing lines in the sand for the fall showdown, when Washington faces a potential government shutdown followed by a Treasury default unless Congress reaches agreement.

The final confrontation on both issues is months away. Federal agencies are funded under a stopgap resolution through the end of September, and the possible broad budget framework is being slowly negotiated with an eye toward fall.

Boehner is hoping to lay the groundwork for blaming any potential government shutdown on Obama.

“Your administration’s sudden demand to increase spending and taxes — yet again — or else shut down the government can only be described as reckless,” Boehner wrote to the president.