By E.J. Dionne - March 11, 2013

WASHINGTON -- Just when our politics seemed destined to freeze into a brain-dead brand of partisanship, party lines started cracking up.

It is common in politics to assume that whatever has been happening will keep happening. But a series of events last week suggested that human beings -- even those of a highly partisan and ideological sort -- bridle at being confined in intellectual straitjackets.

Start with the progress on two of this year's central issues, gun safety and immigration.

It was unfortunate that talks between Sen. Tom Coburn, R-Okla., and Senate advocates of universal background checks were suspended because Coburn can't quite get to yes. But the mere fact that Coburn and Sen. Charles E. Schumer, D-N.Y., were negotiating at all, and stayed on cordial terms, means something. So did the vote that Sen. Charles E. Grassley, R-Iowa, cast in the Judiciary Committee in favor of a bill to make it a federal crime to purchase firearms for another person.

The anti-trafficking measure is the first step toward a sensible gun violence package, and the indefatigable Schumer is not giving up on finding additional Republicans to join Sen. Mark Kirk, R-Ill., in support of a strong bill on background checks.

On immigration, former Gov. Jeb Bush showed what happens when the print deadlines for books are out of step with rapid shifts in the political winds. In "Immigration Wars," co-authored with Clint Bolick, Bush came out for legalizing the situation of undocumented immigrants but against giving them a path to citizenship. His book dropped at a moment when leading voices in his party (notably Sen. Marco Rubio, his fellow Florida Republican) have embraced citizenship as a goal.

I hope Secretary of State John Kerry, trashed by a certain Bush brother as a flip-flopper in the 2004 presidential campaign, was entertained by the sight of Jeb Bush's scrambling to adjust himself to new political realities. But let's be charitable and take the younger Bush's evolution as another sign that the ice is breaking in places where it once seemed 30-feet thick.

This is not only a matter of Republicans moving the Democrats' way. Sen. Rand Paul's filibuster against President Obama's drone policy shook philosophical categories in a remarkably healthy way.

On the one side were Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., staunchly defending Obama against their tea party colleague. On the other, many liberals -- including Washington Post columnist Eugene Robinson -- praised Paul for opening up a debate we badly need.

It's true that Paul's 13-hour speech came with a large dose of right-wing paranoia, its low point being the Kentucky senator's bizarre suggestion that Obama might call in drone strikes against tea party members in the United States.

But the administration has invited attack by imposing a level of secrecy on its drone policy that's not consistent with what we have a right to expect in a democracy. Graham admirably chided conservatives for raising questions about Obama that they never raised about George W. Bush. Liberals should reciprocate by holding Obama to the same standards they would invoke if Bush were still president.

Then there was the get-together over dinner between the president and a dozen Republican senators to ponder a budget solution. It's easy to dismiss this repast as an amiable gesture. But it has been a long time since a group of Republicans said so many gracious things about Obama. My hunch is that this is the beginning of a real negotiation.

The softening of party lines should not be confused with the coming triumph of a timid centrism. On the contrary, the new drone discussion has been driven by an alliance between forces well to both the right and the left of center.

And if Republicans end their intransigence and seek an agreement on the budget, they'll call forth a more vigorous argument from progressives who do not want Obama's desire for a deal to push him toward large cuts in retirement programs. A preview was offered by Thomas B. Edsall in a powerful column online for The New York Times last week asking why, for example, we are talking a great deal about cuts in Social Security but not much about increasing the paltry share of their income that wealthy people pay in payroll taxes.

Hope about anything in our politics seems outlandishly risky these days. But we have had a taste of how less rigid partisanship can enliven and add substance to our debates. We might get to like it.