With little public attention, the two national parties are on the verge of restoring some sanity to the presidential primary schedule and making other changes that could impact the 2012 race.

Besides delaying any contests until early February, the changes would require most primaries and caucuses to be held in March or later and make it harder for any Republican to clinch the nomination quickly.

They would also require date changes by 40 states that held 2008 primaries or caucuses in January and February. Texas still could vote on the first Tuesday in March, but it might find many other states sharing the date.

Both parties’ national committees will meet next month to ratify proposals from special party panels that operated separately but in tandem. The changes would permit only Iowa, New Hampshire, Nevada and South Carolina to hold pre-March tests — but forbid them before Feb. 1.

That would prevent a repeat of 2008, when states rushing to move up primaries led to Iowa caucuses and a New Hampshire primary in early January and intensive campaigning over the Christmas holidays.

Perhaps the most potentially consequential Republican change would reduce the number of winner-take-all primaries — and perhaps prompt some state parties to abandon primaries that attract a broader electorate in favor of caucuses that favor more conservative elements, such as tea party activists.

Chances of GOP approval are enhanced by the likely support of Morton Blackwell, Virginia’s veteran national committeeman and a key opponent of major rules changes for four decades.

He said these changes would slow the headlong rush toward a de facto national primary. “My guess is that this will pass,” he said. But he predicted that requiring states choosing delegates in March to divide them proportionally — or face losing half of their allocation — won’t succeed in its goal of extending the process by encouraging later state primaries or caucuses.

Texas National Committeeman Bill Crocker remains unconvinced.

“I really do not like institutionalizing Iowa, New Hampshire, South Carolina and Nevada” as early tests, he said. “They do not reflect in any way the preferences of Texans” and the national GOP.

He also doubted the legality of requiring proportional representation, which would impact Texas if it kept its March primary. “Unless somebody changes my mind with some really good arguments, I’m going to vote against it and encourage people to vote against it,” he said.

The proposed rules changes require a two-thirds’ majority and can’t be amended when the Republican National Committee meets Aug. 6 in Kansas City.

GOP acceptance depends on the Democratic National Committee approving a similar calendar Aug. 19-20 in St. Louis. The Democratic plan also cuts the number of party and elected officials guaranteed “super delegate” seats. But party leaders expect the main impact in 2016, unless unexpected opposition develops to re-nominating President Barack Obama.

The Democrats would set the Iowa caucuses Feb. 6, New Hampshire primary Feb. 14, Nevada caucuses Feb. 18 and South Carolina primary Feb. 28. The Republicans say the four can vote in February but don’t specify dates.

However, if the plans pass, both parties would hold their Iowa caucuses and New Hampshire primary on the same date.

Republican adoption of some proportional representation, a procedure Democrats have long required for all delegates, could trigger some interesting fallout.

A candidate who lost early Republican tests could stay in the race in hopes of a rebound, as Hillary Clinton did against Obama in the 2008 Democratic race. Mitt Romney, for instance, might have stayed in longer against John McCain that year.

But some Republicans fear it could prompt some states to avoid losing delegates by switching from primary to caucus systems. The requirement only affects the actual selection of delegates, which happens in caucus states like Iowa later in the process.

One big unanswered question: Will some states undermine the new schedule by resisting the changes?

— Carl P. Leubsdorf is the former Washington bureau chief of the Dallas Morning News. carl.p.leubsdorf@gmail.com