Is Marco Rubio serious about winning the Republican presidential nomination?

With Jeb Bush failing to break out of single digits in the opinion polls and more popular candidates like Ted Cruz and Donald Trump seen as unelectable against the Democrats’ Hillary Clinton next year, conventional wisdom has it that Rubio could be the man Republicans rally around.

But it seems the first-term senator from Florida never expected to be in this position.

Weak ground game

The conservative National Review reports that activists in Iowa are dismayed that Rubio is making so little of an effort in their state, which will have the first go at voting in the Republican nominating contest in February.

The state’s caucusgoers are interested in Rubio, but his infrequent appearances and paltry field operation leave lingering doubts as to whether he is interested in them.

Rubio’s supporters claim he is running a different kind of campaign, one that focuses less on field operations and more on television commercials and digital outreach.

But that’s not what the voters in Iowa and New Hampshire want. They are used to sizing up candidates in intimate settings: their diners and living rooms. Other candidates, with the exception of Trump, are doing it the old-fashioned way.

Voters in the first two states are also notoriously slow to make up their minds. Hence Trump’s frontrunner status is fleeting, but Rubio doesn’t seem ready to step in his place.

Not in it for the long haul

Politico previously reported that he has been raising less money than Bush, Florida’s former governor. That could hurt Rubio if the nominating contest drags on for months.

Iowa, South Carolina and the many Southern states that vote on Super Tuesday could give momentum to a hard-right candidate. But a relative moderate could stage a comeback in late March and early April when Connecticut, Florida, Maryland, New York and Ohio vote: states that are less conservative and should favor a centrist.

If Rubio doesn’t have the money and the organization to stay in the race for so long, that relative moderate is almost certainly going to be Bush.

Going after the wrong voters

Old hands are puzzled that Rubio is wooing the Christian right rather than the moderate conservative voters who know that their party isn’t going to win back the White House in 2016 if it nominates a firebrand.

Evangelicals may be overrepresented in Iowa, but Mitt Romney still nearly won the caucuses there with a quarter of the votes in 2012.

Moderates are looking for a standard-bearer. But Rubio is competing with a purist like Cruz.

Surging too soon?

Perhaps Rubio just hasn’t decided yet what type of Republican he wants to be.

When he announced his candidacy in April, this website argued that Rubio has no natural constituency. He was elected with Tea Party support, but is also more at home in twenty-first century America than the likes of Cruz and Trump. He once supported a more liberal immigration regime and still champions conservative education reforms, but Bush is a more plausible advocate of both.

Running for president only five years after he won his first Senate election was always ambitious. Rubio looked more like a vice presidential than a presidential candidate: someone to lead his party in four or eight years.

Now that there’s a chance he could actually win, Rubio may not be up to the task.