The 100-day evaluation is a marker in U.S. politics — superficial sometimes, though often a leading indicator. By April 15, 2015, the tone and motivation of the new Republican Congress may be apparent.

Those first 100 days won't make clear which measures will or won't pass the 114th Congress; no one can anticipate intervening events over the next 600 days.

By Tax Day, however, there'll be a good sense of whether the year will be shaped only by partisan confrontations or if it will feature a decent dose of principled compromises, too.

The last two months offer no clear guideposts. The Republicans won smashing victories in the midterm elections and moved to dominate the dialogue. Then, with a series of executive actions on immigration, climate change and Cuba, along with a surprisingly productive lame-duck congressional session, President Obama put Republicans on the defensive.

Further damage occurred last week, when it was revealed that Rep. Steve Scalise of Louisiana, the No. 3 House Republican, spoke to a blatantly racist group in 2002.

Here are some signs to look for over these next 100 days:

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• The president's approach: Pennsylvania Avenue is a two-way street. Obama's general view of compromise is to seek areas of common ground; there are a few, including trade, but not many. In divided government, compromise works when both sides surrender things they don't want to give up in return for getting something they want. Although the products were flawed, this sort of compromise occurred in the lame-duck session.

The Democratic-controlled Senate is gone and the dynamics are different; can the White House adjust?

• Homeland security showdown: Republicans, especially in the House, will face a crucial test: All of government is funded through September, except for the Department of Homeland Security, which conservative Republicans insisted on carving out as a way to go after Obama's executive actions shielding as many as 5 million undocumented immigrants from deportation. This will be a real test of Speaker John Boehner's control. Republicans won't succeed in killing the immigration action, and they could further alienate Hispanic voters and force a confrontation over funding homeland security. All are political losers.

• Just say no, or craft alternatives: Demands for the repeal of Obamacare or the withdrawal of the immigration order are empty gestures to satisfy the Republican Party's base. Eventually, pressure to offer credible alternatives will build. There's a deal waiting to be had on infrastructure and maybe on corporate tax reform. Immigration may be impossible. On health care, Republicans could enact some conservative-leaning modifications to the law that the White House might accept. Yet that would be unacceptable to some congressional Republicans who continue to dream of killing Obamacare.

• Can this partnership endure? Boehner and his Senate counterpart, Mitch McConnell, have as good a relationship as any recent House and Senate leaders. They are pragmatic, deal-making conservatives who believe some achievements are in their self-interest. Yet the interests of their party caucuses could diverge. McConnell has to worry about the 24 Republican Senate incumbents up for re-election in 2016, almost half in blue or Democratic states or battlegrounds in the presidential race. Among House Republicans, a greater fear is alienating the right-wing base.

There is a possibility that this year could produce a handful of substantive legislative measures signed by the president and a number of other issues vetoed or sidetracked by Senate Democrats; these would frame issues for the presidential race. It's an outcome that could benefit both sides.

As likely, if not more so, is that House Republicans, stung by being called obstructionists, will try to force the president into that role. McConnell wants to get things done, though at a recent private dinner with top party strategists, there was a glaring omission: no mention of Obama, without whom little will be achieved.