Last year, Sen. Ted Cruz (R-Texas) stood front and center in the battle against President Barack Obama’s health care program, leading an effort that shut down the government because the budget bill did not include a provision to defund the president’s plan.

This year, Cruz was the lead crusader against the spending bill again, this time because it did not include a challenge to Obama’s executive action on immigration, which could shield an estimated 5 million people who entered the country illegally from deportation for about three years.

His efforts did not shut down the government this time, but it delayed the vote, forcing very unhappy Democrats and equally unhappy Republicans to work an unusual weekend shift in order to finally pass the $1.1 trillion bill. Cruz's dogged determination to force a vote, unsuccessfully, on Obama's immigration order under Senate rules allowed the lame duck Majority Leader, Harry Reid (D-Nev.), to begin the time-consuming process of confirming nominations on Saturday at noon — when lawmakers originally had been scheduled to be home for the weekend.

Some of the harshest criticisms of Cruz this week came from within his own party – just as they did after the government shutdown  in 2013, which was capped by Cruz’s 21-hour speech on the Senate floor.

"You should have an end goal in sight if you're going to do these types of things," Sen. Orrin Hatch of Utah said, "and I don't see an end goal other than irritating a lot of people."

Why is Cruz – who is viewed as a possible contender for the presidential elections in 2016 – apparently impervious to the wrath of his own party?

Precisely because he is a possible presidential candidate, some political observers say.

Cruz, it seems, is bucking the trend of many with their eyes on the presidency who are trying to appeal to the middle-of-the-road voters, especially independents, as well as the party establishment.

Instead, he is keeping his focus solidly on conservatives, the tried-and-true tea party souls who find his denunciations of Beltway politics – even those of establishment Republicans – refreshing, according to a National Review article that cited Cruz “senior advisers.”

Not that he is giving up on support from some groups, such as Latinos, Jews, women and others who tend to lean Democratic. But Cruz is hoping to appeal to some of them while exciting the conservative base enough to make them as much of a factor in general elections as they tend to be during the GOP primaries.

“His strategists aren’t planning to make a big play for so-called independent voters in the general election if Cruz wins the Republican nomination,” the National Review said. “According to several of the senator’s top advisers, Cruz sees a path to victory that relies instead on increasing conservative turnout; attracting votes from groups — including Jews, Hispanics and millennials — that have tended to favor Democrats; and, in the words of one Cruz strategist, ‘not getting killed with independents.’”

Republican strategist Ford O’Connell told the magazine that Cruz must “figure out how not to lose his authenticity with the Republican base while expanding his reach.”

To be sure, Cruz’s opposition to granting a path to legal status to undocumented immigrants has made him something of a pariah to many Latinos and advocates for immigration reform.

But Cruz’s advisers note that many Latinos are attracted to his views, noting that he won 40 percent of the Hispanic vote in Texas when he ran for the Senate in 2012.

As for Jewish voters, Cruz has made headlines this year with his defense of Israel’s actions in Gaza, even lecturing hecklers at a Christian Arab event he was speaking at, telling them that anyone who hates Israel also hates America. After which the senator walked off the stage.

At a Zionist Organization of America dinner in New York City in late November, Cruz recounted that event, generating cheers from the crowd and chants of “Run, Ted, run!”

The conservative base has proved increasingly important during the GOP primaries, and for the 2012 election, many candidates adopted a stricter stance on immigration during the primaries than they ever had before.

That is one reason, some GOP strategists believe, that while former Florida Gov. Jeb Bush, a moderate Republican, could enjoy wide appeal in a general election campaign, the primaries may prove more difficult for him.

This week, the Washington Post noted that Cruz “has shown an absolute contempt for the niceties of the Senate.”

“And there’s a reason for that,” it continued, “Ted Cruz doesn’t care if [Tennessee Senator] Bob Corker or soon-to-be Senate Majority Leader Mitch McConnell like him. In fact, he revels in the fact that they don’t.”

This week, unhappy Republicans accused Cruz of giving President Obama a present this holiday season — a gift certificate good for the confirmation of 12 judicial appointments, and other long-stalled nominations – not long after the voters delivered the Democrats a lump of coal in midterm elections.

Late Monday, the Senate confirmed Vivek Murthy as surgeon general. Cruz disputed the claim.

"Everyone knows Harry Reid planned to jam forward as many nominees as he could," Phil Novack, a spokesman for Cruz, said by email. "Unfortunately, there are many on both sides of the aisle who would rather stoke stories about Ted Cruz to distract from the more important debate over the president's unilateral action to grant amnesty."

But there was no dissent that Senate Democrats, who must turn over power to Republicans in January, suddenly find themselves in a position to confirm not only the judges, but 11 other appointees before the chamber wraps up work for the year.

“Cruz paints his opposition to 'the way things have always worked’ in the Senate as in keeping with his oath to his constituents and to the Constitution,”  the Post said. Indeed, it went on to argue, he constantly gets confirmation that his strategy is raising his stock among conservatives.

“At any sort of conservative gathering,” the Post said, “he is regularly the star attraction – the one person (in the eyes of his admirers) willing to stay true to his convictions in Washington.”

But some political observers say the party establishment is very likely to work full-throttle to subvert Cruz’s chances of winning the nomination, fearing they will lose another presidential election.

Henry Olsen of the Ethics and Public Policy Center told the National Review that Cruz’s apparent belief that conservatives can carry him to the White House is a “fantasy.”

Olsen said the base isn’t big enough to propel Cruz or any other candidate to the Oval Office, and that in order to have a real shot at winning, a Republican nominee would have to “energize establishment Republicans and people don’t call themselves conservatives.”

The Associated Press contributed to this report.

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